Just buy it all !
It may be that they have not decided on their pricing until it's actually about to be released. For me if I really like something I buy it with no regrets. If I can't afford another item later I remind myself how much I enjoy the item I bought.
I know it's tough sometimes and we are not suppose to have everything. I do invest a sizable amount of $ each month but honestly I really love the game. It has so much for a solo player to do and also offers the social aspect as well. I am so pleased with the art and detail the ESO - Bethesda teams put into every creation in this game. From the armor, weapons, mounts, homes etc etc.
It makes the outfit shop and different ways to personalize your character so much fun too. I am really enjoying the Notable home I purchased recently as well. The detail in everything ! so rewarding.
All the best..
Actually, the reason is to make you impulse buy what you like, not to allow you to plan ahead.
Agreed. You see it in the showcase and then have days or weeks to think about how cool it looks and how much you want it, so by the time it's in the game and you're just moments away from owning it you're probably already attached to the idea of buying it and more likely to talk yourself into spending more than you'd expected (or more than you'd hoped it would be anyway) to get it. Real life stores will sometimes use similar tactics, probably the most common will be encouraging you to hold an item - either while speaking to you or putting the price somewhere you can only see it after you've picked it up. Because once you're holding it you're more likely to feel like it's practically yours, and so more likely to go ahead and buy it.
Of course like any marketing it can have the opposite effect, especially with people who are already cautious with their money. But I assume ZOS think the benefit outweighs the losses.
My advice, as someone in a similar situation, is this: firstly look out for the data mining topics that come up on this forum, they can give you some idea what will be in the crown store in future. Nothing which is data mined is guaranteed to appear and when they'll appear is even less reliable, some things can take months to be released while others are added almost immediately. But it can help you plan ahead.
Secondly as much as possible judge each item on it's own merits - don't buy something just because it's the only horse/dress/furnishing pack etc. you've liked for a while, but equally if there's something you really like don't hold out for a better one that might never come. (Unless you know one is coming thanks to the showcase or data mining of course.)
Finally use the time between the showcase being posted and the item being released to think about what it's worth for you. Since a lot of crown store items are purely cosmetic that will be highly subjective, but I'm sure you have some idea of what you consider a fair price for things. Then if it's below that get it (if it's a lot below that consider it a bonus), but if it's more than that don't buy it.