Free sites:-
familysearch.org - has a good selection of b,m,d records and census. There are quite a few original records on there too. Ignore their family trees, they are generally nonsense.
freebmd - lists civil registration births, marriages and deaths
freereg - list bapts, marriages and burials and gives you transcripts, but very patchy coverage
I use ancestry - it is quite pricy but you can sometimes get 50% off
I also use findmypast -again can be quite pricy
If you join a local library, you may be able to get access to ancestry or fmp through there (even from your own home).