Doesn't matter if you have Illustrator or not. Are you a designer? Are you an artist?
If not, then who cares if getting the material on is cheaper for you, you're losing a LOT by having stuff that looks like ****. I'm sorry, but in the picture you posted... that car is alright for a newbie with a cutter, but looks like complete crap to me. The car would literally look better with nothing on it, than what was put on.
Now, that might sound harsh, because it is. For a reason. This is a professional field, meaning it's not easy, and it takes a lifestyle and a certain flavor to do it right. Just like a lawyer, a doctor, a consultant etc. This is not just buying stuff and selling like retail.
My suggestion, similiar to OPs, find a local shop that'd barter with you. Heck, find ANY shop to barter with and apply the stuff yourself. I'd even do some swapping with you man. Just don't jump in, buy some equipment and try out a new business.... as you'll just end up frustrated and with a lot of poor looking cars.
Hope that helps.