If PCs cant buy... they wont sell too. So the +1 sword he found at 5th lvl will stay with him when he is 10-12th lvl ?
Well...I have a suggestion, based on what I do in my game. While "stores" where you can just pick magic items to buy right out of the DM's guide do not exist...there are some means by which you can acquire those things you think you need as a player.
First of all, wizards and priests in a sufficiently large city (based on the rules in the DMG) will take contract work if they are able to undertake the creation of magic items.
This requires a gather information roll of 10 + caster level of the item to find someone who can make it. Then you have to negotiate with them. They'll almost never have it already made...but will instead have to make it.
If a PC just wants to pay gold for the item...then market price for the item is
four times what it normally would be. However, the PC's can trade other magic items for the magic item they want made...cost in magic items if 50% above market value. (If it costs 10,000 gp normally, you need to provide 15,000 gp worth of magic items).
Lastly, you can obtain a list of items/ingredients (hard to gather) that the creator needs. Provide these and he will sell you the item for gold pieces for straight up market value...or take the ingredients + magic items in trade for 75% of Market Value.
It's important to note that in my world, having rare, expensive, hard to get magical ingredients (appropriate to the item being made) will reduce or possibly even eliminate the xp cost for creating the item.
These ingredients shouldn't be easily obtained though.
Lastly...those +1 items still kicking around when you are higher level, make for great donations to the church when you want a resurrection...or something of the like. Especially to the church of Boccob, which values any magic item.
Cedric
p.s. If you have any questions or want any more details, lemme know, I'll follow this thread.