As you say, we should all learn from our mistakes. But when there's others that have already made those mistakes it's sometimes best to bow to their experience

Whilst I think you're attitude is a good one towards building your customer base, I do suspect that people will take the mick and as others have said you'll lose out and get very fed up with them soon enough.
There is a school of thought that says you should always charge a good price for a good service or product. If you don't, people will mostly undervalue either the service you offer, or indeed undervalue you as well.
Compromise, offer your potential customers a half price first clean

Tell them as you're expanding into the area you're currently offering 50% off first cleans, this should be your normal rate

They get a quality service at a fair price, and hopefully you'll get a return of business.
Good luck
