It might be worth checking out your local library wherever you live. We also have this service in Devon Libraries - and very grateful we are, too. If libraries do require you to be a member to use their computers, they'll usually have a system of visitor or guest tickets.
Some of the information resource subscriptions that libraries take out allow registered users to make use of them from home via the library website - usually by entering a valid borrower number. Unfortunately, probably for sound commercial reasons, this does not apply to Ancestry ... at least, not in Devon.
Now a message from our sponsor: Unfortunately, the motto "use it or lose it" applies to your library (a rich source of information and access) as much as it does to the Ancestry service