It is the middle of the month and paid $3000 for move in, now come next month on the 1st i am having to pay the full months rent. Is that illeagal? I mean to pay over $3000 to live in his place for 2 weeks. Doesn't the lanlord have to prorate it?

Do you have a lease or are you a month tyo month renter? Tell us more details but in all likelihood the answer to your question is yes.

...Tell us more details ...
Like, for example, what state you are in, what was discussed, whether there was any discussion of a deposit, whether you have a written lease, etc.

It may be legal, it may be illegal. It depends on your location, your lease status, how much notice you gave, etc. All details you neglected to include.

And please don't type in all caps.