When I had my machine and fab shop we cash flowed the entire operation, I was 22 at the time. I agree that starting a business in debt is not a good idea. Start small, and grow the business as sales improve, don't get into a hurry. Too many want it, and they want it NOW! Unfortunately for them they were the ones that I purchased items from when the auctioneer was selling off their shops. I was buying machinery, and tooling for an average of 10¢ on the dollar for new.
As Dave Ramsey likes to point out, The borrower is slave to the lender.
My advice is to learn the skills to be proficient in what you want to do before you start offering them to customers,start small, and build the business on the profits. Too many also don't realize how much time the business side gets in the way of doing the work itself.
Advertising has changed tremendously since I had my shop back in the late 80's. Today I can sit here in DaBoonies and sell worldwide through the wonders of the internet. I know artists who sell through Facebook, and do quite well - $500 paintings sold in 15 minutes a few times. How many people still get a newspaper? I don't. Social media can be a tremendous boon to a business if it is used correctly.