In our Pathfinder campaign the house rule is that any item a PC crafts can be sold to a NPC at only 50% of the regular rate. This is the same discount as if the item was found in a dungeon, and is equal to the cost of the actual material costs. This makes the crafting feats useless as a fund-raising source. But it makes them very useful for creating magic items tailored made for the party.
The section on 'Magic Item Gold Piece Values' (p. 549) along with table 15-29 (p. 550) allows the party's crafters to create new magic items with multiple benefits. Use the tables to calculate market price for the new item, divide market price by 2 to get material costs that someone has to provide, and divide by 1,000 to get number of days the crafter needs.