I can assure you that "rounds" are still going strong, as long as they are worked regularly :)
As for pricing, it pretty much is a case of "how long's a piece of string?"
To give you a rough idea, I paid £3500 for a round over 20 years ago that earned approx £330 per clean, once a fortnight.
Another round I bought approx 20 years ago, earned approx £320 per clean once a month and I paid £1000 for it. I sold 3/4 of this work approx 15 years later .... it earned approx £1050 per clean per month and I sold it for £6500.
The above just shows how varied the pricing can be.
With regards to people knocking on customers' doors, once you've been established and a the customers get to know and trust you, these people usually get told to sod off. A few years ago I had a guy knocking on one of my rounds, offering to clean houses for 50p less than whatever the current window cleaner was charging. I think he manged to get 4 houses - all houses that I sacked because they were bad payers, etc. Needless to say he didn't last long :)
Any further questions - feel free to ask :)