MVP does not means cheap.
MVP means "Minimum Viable Product". It is very hard to make viable part on cheap using only contractors. You might end up with "Minimum Crappy Product".
Building of MVP requires a lot of interaction with early adopters and evangelists and that is where contractors really cannot help you. Unfortunately, they require the exact guidance.
Some might say that MVP for some SocialNetwork ver. 245 might be cheap to make - but I think MVP in that space if does not have something very unique it needs to have very very nice interface which you cannot get for couple of thousand dollars.