It appears that the valve has the Delta 1700 trim which it the good one. The other faucets would normally also be Delta so they match the shower trim. Are those prices the installed price or just the cost of the fixture? If they are the cost of the fixtures, then they should be whatever the actual cost is, not just an arbitrary number. The way the cost is determined should also have been addressed in the contract whether it is his cost plus a profit factor, list price, list price less a percentage, etc., otherwise he can make the price whatever he wants to.