Don't expect decent money for jobs like this.
I was asked to quote once. I gave them a figure that was accepted. While chatting with the guy, I was horrified to realise that my "per clean" price was what he thought was my "per week" price (they wanted 3 cleans per week) and we discussed the requirements for a while before realising this. At least we had a good laugh about it when we realised how far apart we were. Business doesn't all have to serious stuff.