Free SAT help?

Anyone know of some free SAT help websites. I hope to get into schools like Duke,Johns Hopkins, Columbia, or Brown and i think i have the grades and everything to get into them, but i need to do crazy good on the SATs, and last year when i took the PSATs i didnt do as great as i thought i would(even though during the time i didnt give a **** about the PSAT and really didnt care how i did on, so that may be why i didnt do as good). I also need it to be free or low costing because i dont have much money to spend