i built a wizard specifically for the purposes of creating magical items (just to see if/how well it works). so far, he's given items he's created to other party members, primarily as a mutual survival tactic (i don't charge them, they're better equiped to do their jobs, we all live to fight another day).
fairly soon, he's going to start charging them half the market price for the items he creates. (actually, he has the magical artisan feat, and keys all magic items to good alignments, so he'll still make a profit.)
i can't imagine trying to sell items to shops. if you usually sell an item at half its market price, and it costs half the market price to build it, you make no profit. (AND you've burned up your time and experience, to boot)
our DM has never limited our wealth, so that hasn't come into play. (it seems kind of silly to me - if your DM lets you have enough money (materials, whatever) to create a magic item, and you have to burn your experience to build it (not to mention time, which is a HUGE issue in our games), why would he count that against you?)
all of this to say: wealth limits have never been a part of our games.
