I went down to my local business start-up initiative, which since i was under 30, after writing a business plan where happy to line my pockets with 1000 pounds. I see your 21, so find out if there is anything like that. They do low interest loans too.
I then got a shurflo back pack (do search) 200+quid, trolley 30, unger pole 90, brush 10, water containers free from ind est, di vessel and resin 120? (live in scotland, water is pure already, so don't need RO!), pipe, this and that, 600 quid probably in all (like Matt, but less diy building involved, though pretty straight forward if you get over sourcing the components i suppose), all out of the back (and side!) of a VW polo.
Setting up is a hassel, but once rolling...
A lone for 600 would be what, less than 15 quid a week for a year? nothing! from my experience i recommend it, its a doddle with a pole, quick, and i think less demeening that 'up-close cleaning'. More 'pro tool'!? (not often mentioned in wfp, trad debate?)
anyway, i digress!, so what i say is, would recommend doing it if you don't mind getting a loan or try out local business initiatives.
Ben
added later:
to address the topic better, i should say i started on ladders, but soon after got wfp afterwards, and glad i did so (early on). wasn't too keen up em really like yourself