Never do mates rates, it's your lively hood. Do you think if you asked any other person whether they'd give up part of their pay check and give it to their mate they would? No chance! It's just tradesmen that are expected to do that! A real mate pays full rate and should think themselves lucky they know a good tradesmen, not take advantage of them.
For me personally a small job like that can’t be priced, it just doesn’t work out right! It has to be done on day rate! Tell you’re neighbour he’s taking the piss mate!! Get him to knock up for you as well the dickhead! Lol.