I receive my British pension here and I haven't lived in the UK for years so can't really compare the two. We are lucky that we were able to buy our house before we arrived so have no rent. Depending on where you want to live you could be looking at least 1000 US dollars a month and you will be expected to pay up front for at least 6 months but there are some month to month properties.
In the UK your medication would be free and I'm not sure how prices compare. Luckily I have not had any medical problems so have no idea on availability but there are good chemists who can get medications. I suggest you bring a good supply.
Living a simple life here is relatively cheap but it does become expensive if you eat out a lot or travel and stay in hotels. I really enjoy living here and live comfortably on my pension.