Yea, I once saw some CHEAP flights on Allegiant to Orlando, but once I looked closer I realized it was not MCO. I hear Allegiant is super "no-frills" - my friend called it a bus with wings.
Yes and they are strictly a point to point airline only -- no connections. You can only book where they fly non-stop to. So if they only go to Sanford from your city but you really want to go to Las Vegas then the only way you could do that would be to book two individual trips.