I started a pressure washing business, with my first job in June '10 (after redundancy). Spent about £10k, which I used to purchase new equipment (didn't want second hand in case it let me down), a branded van, a website, separate phone line, etc, as I also want to present a professional image. I initially took out liability insurance for £1m, but had to increase to £5m for a commercial contract, but that still only costs £90 per year in total. Leafleting has had a poor return; I get most work through the website, recommendations, or neighbours of customers asking 'can you do mine next?'...
I offer a sealing service as well as cleaning and sanding, and have worked on some beautiful and very expensive properties, as well as the smallest of terraces. Encouragingly, I've just won my first regular contract for a block management company. I've also recently added gutter cleaning and garden clearance to my portfolio. However, please bear in mind the work is very seasonal (in my experience), and often hard to come by; I've had to supplement my income doing other things whilst I've been building up the business. Some days/weeks you can earn good money, but if you don't work for periods at a time, it's average money. Not sure this will make my fortune, but it's better than sitting in an office all day... Good luck.