Pull the plugs (good luck with the front ones) and put some oil in the cylinders before you try to turn it over, it's probably well rusted in there. Crank by hand using a socket/bar on the bolt that holds the engine pulley.
With ref to the mice nests above, remove the heater fan in the front compartment where the spare sits or even the whole plastic panel that forms the ducting. Usually lots of leaves and mice nests in there pluse three bug resistors that form the speed control for the blower fan. Those get hot (red hot), add some leaves or a nest and you're' toasty!
For parts, The Fiero store is pretty good for a lot of stuff. Prices might be a little high but hey, if it keeps them in business I am OK with that, at least they are there.
Rodney Dickman also does a lot of custom and upgrade stuff.
For standard parts Rock Auto (online) has always been pretty good although I think it's getting harder to find a lot of the really old or Fiero specific stuff now.
Otherwise it's the mall on here or, god forbid, eBay! Your local (and further afield) Craigslist can often be a source of parts as well.
Anything I might say is probably worth what you paid for it, so treat it accordingly!
[This message has been edited by ltlfrari (edited 03-18-2017).]