There's no limit on paladin possessions, and I think that's good. The class is balanced in other ways, so he won't need to carry significantly less gear than other heroes.
Of course, they might often give away stuff, but I think that's up to the player, and It should be his decision how he spends his coin.
A paladin of Sune (FR goddess of love) would probably buy beautiful objects of art for a steep price (more than they are worth) to encourage artists to make such things, and then would give them away to dalliances or anyone else, just so they have something beautiful.
I would penalize an overly greedy paladin, but I won't put a flat percentage on his income he has to spend (I think roleplayers will play generous paladins all by themselves, and the powergamers will stick to other classes).