Require

Require
 

The president required the money be paid at once. Is it Ok without to in front of be paid?
THe president required that the money be paid at once?

Both proposals are correct.

and the money to be paid at once?

It is OK without the 'to'.
You can include it if you want, but it makes no difference in the meaning.

I prefer the inclusion of the conjunction 'that' (the one found in you're last proposal), but this conjunction is often omitted in American English. I believe I like it because it's used in the Spanish equivalent of this demand.