The economy is a little off, owing to the game getting older, the variety of stuff that can be sold, etc. There are more level 50 vet characters in the game than anything else, so supplies they pick up are ample while lower level stuff can be a pain to find. However, with a little effort you can get the stuff you need.

Shop around

You can join up to five guilds, and it's good to check those shops first so you can help your guildmasters make some money. However, if your personal guilds don't have what you need at a reasonable price, you need to go shop other guilds via the trading spots scattered all over.

The best shops are located (generally) in wayrest, mounrhold, Elden root and Rawlkha. This is where I start when I need something. Remember, the guild store filter will "stick," remembering your last search. If you need dwarven ore, set the filter and hop between traders to check prices. Don't forget to set the quality filter. If you want dwarven oil, that's blue, so search crafting...smith...tempers...blue.

Some items will be harder to find because homesteading can suck up a lot of this stuff. For example, pitch (green wood mat) used to be everywhere. Now, since a piece of furniture takes 15 of them, they're scarce.


Build up a supply slowly

The hirelings in the skill lines are pretty valuable for helping build a supply of the mats. Invest in these points, even on alts, and over time they'll generate tons of useful stuff. Just make sure to either have ESO+ For the craft bag, OR develop a system so your account doesn't get overwealmed with crap. Before the craft bag I simply used one alt for provision, one for alchemy and enchanting, and one for equipment mats.


Ask for help

If you still can't find what you need, ask for help in guild or zone chat. People generally will assist for a fair price. It really depends what you're looking for. Dwarven Oils are valuable, so you might find sellers, but no freebies. Other things, like provision ingredients, are useless, which is why they're not in guild stores. If I see a text asking for bananas, I'm happy to dip into my ridiculous 9k banana supply to assist. But no one lists them in guild stores because it's a pain and you only get 30 slots.


Hopefully that helps.