in my previous job i got asked to build a couple of pcs for them i quoted £200 as i hated working for them and they where minted. Turned out i was cheaper than the normal guy! so i made a nice little packet out of that. If its not someone you know try your luck! If they thought about a pcworld pc you could sell them anything at any price
Through work I charge for parts and £55 an hour for labour. For a cash in hand job i'll do it for £50 if they supply the parts
Whatever I feel like really, depending on who it is and what needs doing. Small jobs - a nice bottle of brandy. Larger jobs, builds etc. - Whatever I need to get an upgrade for my system, usually entailing using my old parts in the new build. I haven't actually bought an upgrade for my PC as such for years.
yes, but they're paying you for KNOWING how to build it. the same goes as when you take your car to the garage to get it worked on... for just building a computer, i'm fairly cheap and charge $50, but if asked to install and test all the software, then it ranges from $100 - $150...still fairly cheap. when driving to repair a computer in my own time, if it's within 15 minutes of where i am, i normally charge $25 an hour with a $25 minimum. over 15 minutes and it's $50 an hour with $50 minimum. anything over an hour away it's a $100 minimum at $50 an hour.
I usually go for ~15-20% of the total value of the parts. But make it ABSOLUTELY clear that they don't automatically get free support for life, unless it's friend/family.