Going to be unpopular but: if you knew the price in advance, you should have had $80 or so and the business should have had at least $10 in small bills/coins.
If you didn’t know ahead of time, and they gave you a price on the spot and you paid at the time, then they should have had the change.
There are 3 things I did that helped to reduce my cancellations:
I realised that the number one reason people called me was they wanted to know how much it would cost for us to come out, and when we could come out.
Once you have them on the phone though, its really easy to develop a phone patter like “Our rates are $X Service Call and covers this much labour and $Y labour price after that. We have availability tomorrow, would you like us to book you in?” and before the customer has a chance to think about it, they have an appointment booked. Problem was, they would do exactly as you describe: They rang around others and made other arrangements after they had some time.
By posting our rates online, and making online bookings available, we had a higher number of customers who we answered the top 2 questions for, and wanted us to come out. There were still a small number of customers who would make a booking and make another booking with someone else and conveniently “forget” about the one with us. This is where our Cancellation Policy comes in.
Our Cancellation Policy pretty lets them know that up until a business day before the appointment, if they cancelled our booking they wouldn’t be charged. The less notice we had, then the more we would charge. We sent this out with every confirmation and reminder email (our online booking system helps with automating this). This gives them a “signal” that if they didn’t let us know asap that they wanted to cancel, then it would cost them money. Did we really charge them? No, because we often have customers who will take a “last minute” booking, but the “threat” of a charge lit that fire under their tail not to forget to let us know.