National Trust: £93.50/year for a family (or £70.12 special offer if you do a direct debit aka automatic renewal every year until you cancel). Whether you're interested in gardens, castles, wildlife, or just somewhere peaceful to relax, our membership gives you unlimited access to hundreds of days out. Gain free entry to over 300 historic houses and gardens, access to some of Britains most dramatic countryside and over 700 miles of coastline owned by the National Trust. Historic properties range from Winston Churchill’s Chartwell, the boyhood homes of John Lennon and Paul McCartney. Countryside areas include significant parts of the Lake and Peak Districts. Coastal areas include the iconic White Cliffs of Dover and St. Michaels Mount, to name just a few.http://www.nationaltrust.org.uk/membership/
Royal Oaks Foundation: The Royal Oak Foundation engages Americans in the work of the National Trust of England, Wales and Northern Ireland, one of the world’s largest and most progressive conservation organizations. IF you do not want to do the direct debit route directly via the National Trust, you can join through Royal Oaks, receive all the same benefits as other NT members, and pay $115/year for a family. Not only is it cheaper, the money you spend can also be a tax deduction (under donations).http://www.royal-oak.org/join/
English Heritage: £82 for a family membership (up to 6 children under the age of 19). With English Heritage annual membership you can explore over 400 castles, stately homes, ruins and more for free! Sites include Stonehenge, Dover Castle, Battle of Hastings, Audley End, to name a few.IMPORTANT: English Heritage members can gain half-price admission to Historic Scotland, CADW (Wales, e.g. Caerphilly Castle), and Isle of Man attractions during the first year of membership and free entry in subsequent years. Don't forget all the other discounts (look under "associated attractions", e.g. Discount tickets to Castle Howard, Woburn Abbey, Duxford, that you can get with your EH membership:http://www.english-heritage.org.uk/support-us/members/benefits/
Scotland Explorer Pass: If you plan on hitting a lot of major sites in Scotland (and are not members of the English Heritage), you may want to consider getting this pass. Check the website for pricing details:http://www.historic-scotland.gov.uk/index/places/explorer.htm
Wales Explorer Pass: If you plan on visiting many sites managed by the Wales government, and are not members of English Heritage, you maybe want to consider getting this pass:http://cadw.wales.gov.uk/daysout/explorerpasses/?lang=en
Merlin Pass: Unlimited entry to Sealife, Legoland, Thorpe Park, Blackpool Tower, and others. Merlin Annual Pass UK brings together 30 top attractions, making it the UK's biggest attraction. With over 100 roller coasters and other rides, 45 million LEGO bricks, 80 waxworks, hundreds of marine creatures and more:http://www.merlinannualpass.co.uk/
Bite Card: FREE discount card for used at participating train station eateries, e.g. Burger King, the Pasty Shop, Upper Crust:https://www.bitecard.co.uk/