[gn1220]

$500 sounds a little high so you might want to call around. The pump itself is probably $100-$200 so the rest is labor. If you've never done this kind of work it would be best left to a pro. If not, just drop the tank, pull the pump out of the top, unhook the lines and wires, put the new pump in and hook it all back up. Can't imagine it would take a pro more than an hour to install a pump. $100-$200 for the pump + $75hr labor = $175-$275. Call around first.