If you try suicide doors on the cheap, you'll get just that - suicide.
For good lambo kits, you are looking at $1500-2500. Most of those kits were made for rice mobiles so some refabrication is necessary to fit the Fiero.
www.v8archie.com does suicide door installations. I don't think he will sell a "kit" for much fabrication is needed and he does not want the liability issues for a bothed installation. The install is in the $3000 range.