Me and my bike were chatting the other day about him having new tyres as the 20mm Gatorskins he had were shot and I didn't like the brake calipers: plus he needed new brake blocks which would cost me £8.00 so we worked out a plan.
I only have either Conti 4000's or Michelin Endurance Pro's spare (at £60 pair which I thought was too much to spend on him as he only cost me £62.)
So what we agreed on is this, I would give him the Endurance Pro's and in return I'll buy some Shimano 105 calipers at £22 (out of his pocket money) so I would save the £8.00 on buying brake blocks making the calipers £14.00.
This now makes sense so he's spent £22.00 on brake calipers, £8.00 on inner/outer brake cables and £10.00 new hood/levers. Total £40.00 for bits and £62.00 buying him in the first place so we are both happy.
I'm not going to charge him the price of a saddle, pedals or bar tape as I have all of them so it won't cost me - he's a lucky bike to have found me!