For a domestic cleaning service...
I'm working on the copy for a flyer and I want to include an incentive/call to action.
I want to say "Call today for £20 off your first clean."
However, this only applies to the deep clean that starts off what will be an ongoing thing. There is no obligation for a client to have us come back, of course. If, for any reason, they feel like they don't want us back, I would only want to know why for purposes of improving the service. But, there is nothing that obligates someone to continue after that first deep clean.
The point is, I am seeking to add regular clients who will be repeat income and I want to give the "call to action" that will spur response. One-off deep cleans are not the bread-and-butter of the business and I would like to avoid discounting that service.
I think that a customer would be very angry if it in any way mislead or appeared to mislead and be "slick." So! How do I word it so that the client understands that this offer is for the first clean of many?