I don't know who "they" are, but a car that starts and runs for $1100 is remarkable. Used engines cost that, or more. An entire car for that is amazing. Don't expect it to last much longer. If you get a few thousand miles, you got a good deal. On the other hand, the fact that it still runs suggests that someone took care of it before you bought it. It could go another hundred thousand, but don't bet on it.
Take it home, change all the fluids, replace the filters (air, fuel, etc), and cross your fingers.
Good luck!