Price is discussed regularly on here.
The idea is to go for the top end of the market and get high prices say 40p to 60p a square foot plus protection for not breaking their windows while you are in the district for next three months

You may find it advisable to start at slighly lower prices to gain experience
Looks like you have invested in a quality equipment rather than going down secondhand route so you should reflect this in your pricing
Use The Search facility at the top
What do you know about marketing, You have started right by contacting your friiends and family. When I worked in the Insurance industry the theory was your lifetime contacts should give you enough work through their referral contacts and this should be an ongoing chain that never breaks . So in THEORY you will have no need to advertise well done.
If only THEORY worked for all. Not knocking it but I know of only one carpet cleaner who claims he started with his first customers and never has had to advertise, or promote his business