If my friend and i (both 21years) wanted to open a non licensed daycare?

Check the laws where you live. Opening a day care is a lengthy procedure, and includes extremely strict licensing procedures (in many places). I would exercise caution if/when trying to get around licensing.

it totally depends on the state you want to operate in. In California, for example:

Family Child Care Home
A family child care home is operated in the licensee’s own home and provides non medical care and supervision to 14 or fewer children in a homelike environment for less than 24 hours per day.

That’s from the Orange County web site.

I have a child in a licensed day care in San Francisco, where everything is expensive. So it is hard to gauge how much you would make, but in SF a young child’s day care runs about $400/wk, or about $10/hr.

One thing to keep in mind, even if you plan to open this center, is how you will convince people to leave their kids with you. The licensing process has the power to convince prospective parents that you are on the up and up. Since you are both quite young, it might be a challenge to get people to trust you with their children. With all due respect to you, I know that I wouldn’t trust two 21 year olds with my son on a day to day basis without impeccable references.