Depends what you offer, if you are actually going to go there and do the work, then charge $75. I charged a flat rate of $100, and that usually included about 2.5 hours of work, if they didnt have a high speed connection, I wouldnt do onsite work. I also charged $50 for wireless setups. If they had high speed I charged $25 for a month of remote followup service if they had high speed.
I also included a mini-lesson, a booklet of about 20 pages of common Internet terms, history, some common pitfalls, etc. Also a lesson on comptuer shopping, and basic habits that should be adhered to.
I did the mini-lesson because the danger is that you will clean everything off, then the next day they will click on the magical "winfixer" popup. Then call you and complain your didnt clean it.
Also, I wrote a script that would run programs every 30 days after WX startup, automated Spybot and a few other programs because no matter how easy the program is to use, if people dont use it regualrly then they will always be confused.
I never accepted an jobs from people I worked with, that is just a shat storm waiting to happen. I tended to go more towards the elderly couples, 50's plus. Elderly people are more willing to shell out the cash, and they really appreciate the personal touch (they also tend to have less spyware and as such follow-ups are rarely required) - I advertised the service at few RCL, and senoir homes - dont advertise the service any more but I still get a few referral calls every month and its a nice hidden income to spend on saving up for a condo

(thank you ING).
MYK