This may sound a little fishy but I assure it is fully legal otherwise it would have been dealt with already by Sony.

First of all you will need to know someone with a PSN ID, Credit Card info filled out, and has bought thing from the PSN Store. Next your friend most Sign in on HIS account on your ps3. To do this you must first create a new account, (User 2) then click the Join Playstation Online. Then when it prompts you if you already have a PSN ID, click yes, he has to sign in with his Email that he used with his account. Once done that Sign in, and go to the PSN Store, once there go up to the top right and click “View Downloads”, once there he should see everything “HE” downloaded EVER(Should and HAS to be what HE download ONLY). Than just pick and choose what you want to download. Once you have, install it, now you have everything on your account as well, and he can delete the new account, or leave it so you just download everything he has (if he trusts you enough) and vice versa.
I hope this Tutorial helped any questions please go to the Your Thoughts Sections and ask away.