A lot of the things are account wide so it doesn't matter if you use them or not -- like cards, engravings, runes, the adventurer's tome, all the collectables, your silver and gold, it's there for all of your characters.

I ended up stashing most of the potions and things in my storage too. They're mainly used for the harder content later on. The percentage potions in particular are best kept for later as in certain end-game activities you can't use normal potions when in them, only the percentage ones. (the ones that do, say 30% health rather than 800 health.)

Gold is theeeee currency for trading and for a lot of your stronghold. 3 is a good price. When you list something, there is the fee taken out of it and the person selling it will only be making 1 gold off of it, so can't really get much cheaper than that unless they want to sell at a loss.

You'll earn a lot more gold later on as you reach level 50. 🙂 I reached 50 with about 100 gold to my name, then it zoomed up to 1000 just questing. The main ingame way of earning gold, if you weren't trading for it on the marketplace, is to do the daily and weekly quests. They'll reward you with Una's Tokens which you can give to a vendor in exchange for gold.