I think it depends a lot on what you think you will get out of it? Like you, I'm a casual player and I just enjoy 'losing myself' for an hour or two - whether questing or crafting or whatever.

I've recently purchased a 2nd house - primarily so that I can add all the workstations (it's a tight fit in the 'free' house). I have little interest in furnishing the house, but that's just me.

Furntiture (well workstations) can be bought for Writ vouchers but they are not easy to get and expensive to buy. I eventually bought ESO Plus as that gave me a) more DLC and b) a few thousand Crowns which is useful.

In short (imo), you don't "need" to spend any actual real money - however, without it, I suspect it will be a long and difficult 'grind'.

Hope that helps.

Okay... Guess I'll chime in on this. The thing is though, it isn't a straightforward question to answer. There are too many variables and each player approaches things from a different point of view. So it's kinda hard to say, it all depends on how you approach the game, how often and much you play, and what activities you do when you do play.

Bottom line is, that housing can be done cheap. As others have mentioned, there are free houses, and many homes from the initial patch can be bought for fairly low amounts of gold. But.. Well, you see - this is the part where it gets complicated, budget building is going to face restrictions. Lot of restrictions. There is still tons of stuff you can do on the cheap, but chances are, that while you fiddle with housing, a sudden inspiration might hit you, an inspiration that is going to cost an arm and a leg in gold. Or fairly signification chunk of real life currency.

The thing to keep in mind when approaching housing is, that it is by design a sink. A gold sink, a time sink, a material sink, and a real money sink. Housing is a veritable cash cow for ZOS, and it is really really really heavily monetized, and there are slew of people who do spend hundreds of bucks on it regularly. All those new 100 buck mansions they keep churning out, and all those special furnishing pieces costing anything from 20 to 60 bucks in real life currency. Consider this as an example:: I have visited several homes that have all Mundus Stone furnishings - that is 4000 crowns per stone, and there are 13 of them. That is a lot of money, even if they were all bought with discount crowns.

So keep in mind that a lot of things are crowns only because lot of people approach ESO more as a hobby rather than just a game they play. A hobby they can spend couple of hundred bucks on each month since it is their primary past time. And ZOS caters to these customers by selling all those expensive bits of furnishings. Sure, you can try to buy crowns with gold, but there is always a risk involved with that. There are reputable channels for such trades, and a lot of people do it that way, but it isn't any cheaper in the end. Time is money as they say, and one must ask if grinding for gold, so that you can buy crowns, is a sensible way to spend your free time. Especially if you are limited on how much time you can spend playing. Real life, work, family and friends limits the hours one can spend online for a large number of players.

Another thing to keep in mind, is the time and material sink build into the system. Furnishings need a lot of materials to construct, and the blueprints to do them are not all that easy to find either. And some of them are ridiculous rare and require insane amounts of monotonous grinding. At this point there are thousands of plans, and it would take enormous amount of time to grind all of them. Most players don't even try, and those who try to collect them all, usually resort to grinding gold and buying them from those who chance upon them and are willing to sell them. Lot of plans cost 100k gold and more. Plenty cost 500k or more.

Not that the plan on itself will do you much good. There are also other materials involved, and furnishings take up a lot of them. And some require quite expensive and difficult to come buy bits to build. A good example is Culanda Lacquer - it is required for all Alinor style pieces and pretty much is only available from the daily quests offered in Summerset. On EU PC server, the price for them starts at 2000 gold per piece. And purple furnishings require two for each piece. So if you plan on doing, say 200 pieces of Alinor furnishing for a build, that's easily over half a million in gold just in those Culanda Laquer pieces. It's either that or grinding dailies in Summerset with fanatic fervor. So ask yourself, how long would it take to do 300 or so daily quests in Summerset, at the pace you play, and then ask yourself is it worth it.

I wager that most players who interact regularly with housing system grind Crafting writs on multiple characters each day to fuel the expensive habit that is housing. Crafting writs is the easiest and most reliable way to make lot of money fast. It takes a fair amount of effort to set things up so that you have several max level crafters available. But once you do have it set up, it gives you a steady and substantial income.

And having millions and millions in gold will come in handy. My own "main house" has cost me at least 20 million in gold by this point. Probably more, now that I think about it. This is in direct purchases of furnishings, as well as in buying materials and plans. And I have no idea how much gold I have invested in housing, in materials used and plans learned, that I could've otherwise sold in a guild store.

Which brings me to my last point - If you are on limited time, can't invest the time it takes to farm the materials and plans and grind the gold necessary, and don't have several million gold available to throw at the project (And are not willing to invest hundreds of bucks in real money eitehr), then my advice is to not construct your own furnishings. You can find most of the things for reasonable price in guild stores. And if you look for a housing enthusiast guild, you will find plenty of people who have invested the time and effort to collect all the plans and farm the required materials, and are more than happy to sell you the pieces you need for a fraction of the price it would take to learn the plans yourself. And If you are doing a smaller house, chances are you only need one or two of each item.

I have, on more than one occasion, done the calculations and evaluated whether it is more sensible to sell a rare furnishing plan to a completionist, or to learn it for myself. Back when Morrowind chapter released, for example, I sold several purple plans because they were super hot at the time and I could make tons of money from them. A good example is the filled bookcase plan - I sold that for something like 400k gold, and then used some of that gold to buy 10 of those bookcases for about 10k per piece. I didn't learn the plan, but I got all the bookcases I needed and still made a profit of 300k gold.

To sum it up, housing is designed to be an enormous time and resource sink. You can have a lot of fun with it, but since it si designed on purpose to be extra grindy and time wasting, it can be hard to do if you are on limited time and are not willing to invest real money into it. Also, the whole system is constantly getting new layers as more and more plans get released. I stopped all attempts to keep up with the release pace for those things. It just takes too much time to be worth the hassle, and I am not willing to invest the amount of money the system asks. Thus I haven't really interacted with the housing system for almost a year now.

Still, if you keep all that in mind, keep your goals in check, and plan accordingly, you can get a lot done with a reasonably small amount of gold. And as long as you don't worry about collecting the mats and plans yourself, and join a housing guild where you have access to players who can build the stuff you need, it wont take too much time either and you can concentrate on the fun part - i.e. decorating your home.

Finally, keep in mind that this is based on my experience. YMMV As I stated at the start, it all ultimately depends on how you approach the game. Back when I was more active, and did crafting writs on 10 characters each day and then played for 3 or 4 hours doing this and that, random dailies, bit of farming and some questing and selling and buying stuff in guild stores. Back then I made well over 100k each day, thus spending tens of millions on my homes was not that much of a biggie. But now, when I play couple of times each week and don't always do crafting writs when I do play, and pretty much just PVP, housing just isn't feasible anymore. Not at least on the level that I want to do it.