Could I make the point that the 1901 census is actually included in the Ancestry.co.uk subscription, so, for about £69 pounds a year you get access to all the published censuses, 1841-1901, plus many other less comprehensive databases. Unless you are researching within a very restricted area, I can't think you could do better than an Ancestry subscription plus the freebies at LDS and Lawson and FreeBMD