Hi gran
I pay £18 a month to ancestry via my debit card, it goes out on or after the 1st of each month but if at any time I want to suspend using ancestry for any reason I just ring them a week or two into a month and ask them not to take the payment for the next month. For that I get full international access, which to be honest I don't really use an awful lot, but then I never quite can predict when I would need it.
As craft says, you can access most of ancestry.co,uk's resources free in your local library, that is the service I recommend people who are just starting out as they won;t be wasting a subscription whilst they learn how the site and the records work. There are drawbacks of course, like limited access during busy times or restriction on opening times in some smaller libraries , but generally there are also people in the library who can offer help and support which is useful.
The 1911 census cost a fortune to be transcribed and the work took along time, find my past have invested alot into offering it on a subscription, but you don't need to use their site, you can use the 1911 site to access the records in smaller chunks by buying pay as you go credits.
I have not read that ancestry.co.uk intend investing in the index and I would imagine the find my past deal has exclusivity clauses built into it, but I could be wrong.