The Canon AE-1 isn't worth much.
- not many people shoot film. It is really a niche market.
- The lenses for the Canon AE-1 (FD mount lenses) aren't made any more and can only be bought by second hand.
- THe meter tends to break rather easily.
A lot of students buy it for their photography classes because their instructors want the students to use film cameras. And this is much cheaper than many of the other film camera options out there.
THere is a market out there for these cameras, but it is a very small and specalized market. And they are often sold for parts.
IF you are interested in selling it, you have to make the buyer know that the camera is in good working order. Meter, mount gaps, sealing. OTherwise, most people might not give it a second thought.
Look at this website, it sells new and used cameras. It is probably one of the biggest sellers in America. http://www.bhphotovideo.com/c/browse/Used-Equipment/ci/2870/N/4294247188
A well conditioned AE-1 is being sold by a commercial company for around 170 USD. As a private seller, you know you can't hope to a price anywhere that high. This company also provides service warranty.
The other guy has already quoted ebay too. I wanted to give you another perspective to consider what kind of people really buy these great cameras.