Kenny, welcome to the UAMCC. Please introduce yourself on the first thread and fill out your signature.
Unfortunately, there is no magic number that you will find on here. As much as any of us would love to help you out, it's all up to you my man. My best advice would be to go out there and do a sample area and see how long it takes you. Then figure out how much time it takes you to do the entire thing, including having to move your equipment down the street, find another water source, are you catching your waste water, etc. Then there is fuel, any chems that you may use, your liability insurance, workmans comp if you have employees, travel time, etc. Figure out how much you want to make an hour doing this, and go from there. If you can do lets say 1000' per hour (don't know your speed or equipment, just throwing a number out there) and you have 35,000' to do, multiply what you want per hour by 35 and possibly add a little to cover any extras. Everyone's prices are different. I may be a little less per hour or a little more per hour from the next guy, but it all depends on each person. Not everyone has the same equipment, same technique, and same overhead costs. A guy cleaning a driveway using a wand and a 25 degree tip at 3 gpm will not be as efficient as the next guy who is using 8 gpm hot water with a 30" surface cleaner. Both can get $200 for a driveway, but the first guy is going to be there all day, while the second guy will be on his 3rd one by lunch.
Dig around on here and see what you can find - there's plenty of valuable information on here to help you. And there are other forums online that are extremely resourseful as well. You just have to do like the rest of us....read, read, read. And when you are done reading, hit the search button and read some more.