A few suggestions from a businessman:
In response to your concerns about being stiffed/dealing with jerks- you may want to selectively cultivate more of a business clientele. If there are many small businesses in your area, they undoubtably have computers which have constant problems- usually just from lack of routine maintenance(antiviral,defragging,etc) which are easy fixes. Price out the comp, then underprice them slightly and play on that. Many businesses have been burned by high priced repair guys. You'll have to be acessable though, and businesses are used to paying either by invoice or by credit card.
A credit card account can be cheap. A monthly fee of $6-8 dollars and a small percentage of your total charges. No expensive eqip needed as the slips can be deposited at your bank.
Finally, visit every doctors office in town. Federal HIPPA regulations require all medical claims to be sent electronically by october. Most docs are not very computer literate and are scrambling to get connected. Alot of companies out there are making fortunes selling doctors computer networks that are ridiculously overpriced. Tell them you'll set up a small network that is HIPAA compliant with online access or debug their current systems, or do regular maintenance, and if you charge a reasonable fee, you'll get lots of business
One final hint- If you visit the docs offices, don't expect to talk to the doc. Be REAL nice to the receptionist(flirty) and give her a professional looking flyer to give to the doc describing your services then stop back in about a week and pump her for what the doc needs
