Well...
Im 14, i have 2 jobs to fund my paintball life. There is no way i could pay £25 a week to go paintballing to be honest. Well i could but not without great difficulty.
At 13 i got a job at the local food garage by going down and asking the manager myself. Then i quit that to go work in a pub washing up, only quit the garage job because it was on a saturday. I then quit the pub job as it was only £3.50 an hour and went to a different pub where i get £4.50 an hour now.
The only reason i got these jobs was not being scared to ring up and ask the manager. Ive never rang up a place where they have said no we havent.
The second job i have is at my local paintball site where i take out spare guns to the games and just hang around picking up pods and cleaning dirty guns etc. its really easy to get a job. Just ring your local pub that serves food and ask for the manager and ask if they have any washing up jobs.
Thats what i would do, dont go buying and selling stuff until you have the knowledge of how much stuff costs and is worth properly. Plus its a risk doing that as you can easily loose money, trust me i did.
Car washing is a good idea, i tend to do that if i need like an extra £10 to go paintballing. Or just ask my mum
Hope that helps,
Jord