jimdean

Have you been a resident of your state for a year? If not, the college may charge you non-resident tuition, which is even more expensive that regular tuition---and some schools won;t let you change the non-resident status you originally enrolled under, even after a year. Establishing residency at some Community Colleges may be difficult! Here's a sample of what California Community Colleges require (your state may vary. It says you would have to be an LPR for a year): http://www.smc.edu/EnrollmentDevelopment/Admissions/Pages/Residency-Requirements.aspx

You can apply as long as you have green card in-hand. EAD or receipts won’t work. 
If your family’s income is low enough (I may be wrong but I believe it’s 50k) you will get a pell grant (around 6k /year) and you may qualify for your state grants. Rest of it are sub and unsub loans 

FAFSA is just only the online form which you fill out, and it link with school code. The school base on this information to give you an award( federal grant, state grant..). You can get around 6k from federal grand for a year( if you 're full-time students). Loan is just an option.

If you have a green card then yes, you can apply. It's still not a free money though. Fafsa will only show you what kind of aid are you eligible for. Probably a lot of it will be student loans. Just saying  (I found out a hard way).