yes you have to have a disclaimer, cause of anything that could happen to their computer and also add whatever you want in the fine print; no one is going to read it anyway
ill repeat my suggestions from the chat,
45$ for home visits, flat fee. or 25$ upto 90 minutes and 20 more for the rest of the time ($45 total for jobs more than 90 minutes)
there are lots of inexpensive places with decent presentable clothes (target)