The reason that it is so expensive is (1) it is a cartridge that contains the fuel pump, the fuel level sender, the pickup and sock and the tank outlet and (2) it is so expensive because the can...

Go to EGAY and search for "fuel pump" and cavalier. You will find a bunch of offerings...some are GM part numbers, some are AC brand (which are exactly the same as the GM since AC makes both) and some will probably be off brands like Carter, Airtex, etc.

You should be able to pick up an AC cartridge for about $200. Installation is pretty simple IF the gas tank is near empty and you are not smoking.