My roommate is moving out on the 15 and it's the 1st he said he won't pay rent this month. There is not contract for him. Is there anything I can do to get him to pay?

No written contract. You nevertheless have an unwritten but express (or possibly implied) contract that each of you will pay half the rent. The problem is that he plans on breaking the contract. In that case, normally the only thing you can do is to pay his share and then take him to small claims court.

Nope that is the prioce you pay for not including friends on leases.