An idea for you - why not offer basic PC fixit advice and charge a nominal fee for it, and you can accept payment via PayPal to make it easy without the need to open credit card merchant accounts. From local sniffing around, a basic tune up and tweak by a computer tech is typically $60-$100, so do it for $25 and hold off until payment is received. Most people will happily pay $25, and PayPal is secure - they are not required to disclose (to you) credit card or bank info, address, etc. etc.
A thought