Hi,
It's hard to tell you the exact price your car is worth because you're not saying:
-The mileage!
-The options (Power mirror, power window, power lock, cruise control, Air conditionning, Power lombar seats, the radio you have (with or without equaliser), sunroof, t-top, motor you have: original 2.8L V6 or a swap, manual (4 speed or 5 speed) or automatic... etc.)
-The colors and any esthetics (If they are things that are broken or things that are in mint condition).
-If you customised something or if it is stock.
-And added some pictures.
-The frame rust it has is a huge factor.
-If you have a problem with it.
As you can see, there are alot of factors and answering to these question will help getting a right price.
Though, I could help you by giving you a right price (I have my car and I'm not interested of getting an other Fiero... for now...

) I watched the market closely before buying my car. I'm still getting myself informed on the market price of fiero stuff.
If you want to sell it is your decision. I can only tell you that because of the high price of gas (Maybe other personnal factors) the Fiero community is shrinking. There is less people that have Fieros, but more fieros owened by one person. As i was saying, because of the price of gas and the economic fall, people are selling there Fieros, (Might not have the monney to invest in them, monney to drie them or they really need monney). Therefore, alot of cars are not up for sale. This means that the prices gets lower. You might not be able to get as much as you want for your car than you would normally would.
I hope this helped, if you still want your a better price, answer these questions and I'll try to help you...

And pictures would help...

Fred