Roth IRA questions..

[SubaruSTiMike]

Hey guys, I'm thinking about putting money into a Roth IRA account, I know I can't take out the money until I'm 60, and I can only put a max of 4,000 dollars. Is that a max of 4000 a year? And every year I can put in 4k? Also, does the money that I contribute have to come from a job and the moeny is already taxed? Thanks. How many percent yield does the Roth IRA give? I keep hearing "if you put in 4k now, you can have a million in 50 years " (granted a million in 50 years probably won't be as much because of inflation). DOes this statement mean people put in 4k in their Roth IRA and let it sit and grow without putitng more in?