Good motor n trans, just wont start for some reason

The car has been sitting for a few months since it won't start. Multiple people have tried to work on it but none have actual auto mechanic education. I can say it was a great car for the 5 years that I drove it but I'm over waiting for it to be fixed. I'm looking for a new to me car n thought if someone out there knew what they were doing it could still run for a long time. Asking 800 obo. It's a 2001 white Buick LeSabre. The interior is dirty from all the guys who worked on it, but it's all there and just needs a good scrub and reassembled.