I would advertise, "If you want a £10 job get a £10 man, if you want a really professional clean then call Tel "
You could go even further by putting "how much did that carpet cost? if it was the cheapest carpet in the shop then call the cheapest carpet cleaner, if it is your pride and joy then call Tel, professional cleaning doesn't have to be expensive it is infact affordable if done correctly WILL make your carpet look and feel like new again"
Shaun