[dogslovetrucks]

Depends on a lot of things. What did they do to make it ready for "long term" storage? I would hope if it was professionally done, all the basics would be covered. Replace brake fluid and oil; swap all your filters, gas it up and give it a try. Gas tank was emptied I hope- if no, any gas in there is now varnish. 3 yrs isn't THAT bad- If by chance it's an auto, you have a few more steps (drain
In all likelihood, it's OK but use it to your advantage when you are discussing price (...um, I like the car but the engine may need rebuilt and that's like...$20k...)
You can Google restarting a car from storage and likely find 100 things I didn't mention. Post pics if you get it.