Closest thing i've done to ripping off a mate was buying a £120 pair of bike cranks for £35. He offered me them for £45 and i knocked another tenner off, despite him easily being able to sell them for nearly double that. To be fair though, i do give him a load of random stuff like brake pads, train fairs etc... plus plenty of aggro for him being ginger
Generally though, me and my mates all look out for each other and what goes around usually comes around, so its better to help them out and have the favour returned later than to stiff them and have them do the same to you.

Generally though, me and my mates all look out for each other and what goes around usually comes around, so its better to help them out and have the favour returned later than to stiff them and have them do the same to you.