Um... You don't pay grants back, you pay loans back. Definitely try to stay away from loans if possible. Any extra income you wind up making due to your educational qualifications will just go to pay off painful debt. There is no quicker way to become a wage slave than living under debt, be it student loans, new cars, over indulgent houses, etc.
Just keep in mind that college isn't really necessary for most jobs. Furthermore, it's unlikely that you'll actually learn a lot that you don't already know in your preferred field. That's just the nature of the system though. College is big business anymore, and profits come at the expense of real education. It never hurts to have that little diploma, but it's not the instant passport to success that many make it out to be. Hard work, charisma, and experience is still needed and trumps assumed education every time.