You can compare prices online at any of the big box parts store's websites.
14:1 compression
I know that on a '96 the fuel filter is an in-line type near the fuel tank. As Pontiac hasn't really altered much on the Sunfire in over ten years, I'd suggest starting there.
Coolant is all pretty much the same from manufacturer to manufacturer. Check your owner's manual to find out the right mixture for your Sunfire
Your best bet is to check prices on some of the big box parts store's websites.
4.5 quarts
I paid $3,500 for mine. Kelly Blue Book for a 1996 Pontiac Sunfire SE Coupe is $3,250.00 retail.
A 2001 Pontiac Sunfire requires 1.8 quarts of DEXRON III fluid for the 5-speed manual transmission.
150psi
50-70 each
32 psi
I'd try to find one in a junk yard. I wouldn't expect to pay more than about $10 or so.
should be about 42-45 psi at idle, will change with vac line to fuel pressure solenoid disconnected