Went recently to help out a local client of ours who we both host and Id personally beforehand designed their site,who had had problems installing a program to their computer. I'd said it was free was there practically 10/20 mins... he'd subsequently slipped an envelope containing £200 with a note into my work diary... due to the kind of person I am id not have accepted it out right as he was aware so rather cheeky.. and as he refuses to take it back...

Had a few others like that but try not to make a habit of it.