some dude came to my door with a window washing service and my mom paid him $90 to wash all the windows on the first story of our house.  it took him like two hours and he did the inside and the outside.  that's $45/hour. freakin ridiculous.  all you would need is a business license, some flyers, a bucket, some towels, some ammonia, and a squeegee, and you can pocket some bank.  i'm gonna do it this summer to pay for my car next year when I go off to school.
Always remember. . .Pray for snow