I don't want to disagree with what you are saying but what happens if Mrs rings 3 companies and they are all yours? then she decides on the cheaper option then you do a 'cheaper job' based on her budget and it's not quite what she wanted (usually they are like that! the cheaper the job the dirtier they are) and you have Aquamagic on the side of the van, 2 + 2 could equal 5 in her mind.
Why not have a company selling at higher prices and see how you go? that's what I did, you'll be surprised at peoples perceptions of cheap cleaning. Okay you'll not get innundated but at the prices you'll get you can afford to get 1 job and drink their tea all day!
Shaun