How to put free games and movies in psp slim & lite?

i recently got a psp slim & lite but i dont know how to put stuff in it. i don't want to buy umd's because they're really expensive. a friend of mine told me that i can put free stuff that can be downloaded from the net but i have to modify my psp first in able to do that. My friend got an old model and he only knows how to modify the old version. he also added that the psp is like a computer that has a modem, and once i do something in it and didnt get it right, it will never work anymore. can anyone pls help me to modify my psp. i need exact and guaranteed procedures pls. i dont want to wreck my psp so can someone pls help me. i will greatly appreciate all the help. thank you all in advance and Godbless!