Generally, the United Kingdom can be more expensive place to visit than many other European destinations. This is partly that the average salary in the UK is one of the highest in the world and partly that Sterling (GBP) can be relatively high in value in relation to other currencies although the pound has declined slightly in recent years. In early October 2011, the pound sterling (£1) is valued at USD 1.55, Yen 117.8 and nearly AUD 1.62 and maintained a value of €1.15. Visitors from the Eurozone may find food prices on a par with those back home or a little cheaper. The same cannot be said for petrol or travel by pulic transport as Europeans may find this eye wateringly expensive compared with.back home.    

Travel 

Travelling by car is not going to help budget travelling, currently petrol (gasoline) costs £1.35-1.40 per litre (approximately $7.50 - $8 per U.S. gallon). The best way to travel on a budget is advance rail tickets or by coach (long-haul bus). Advance rail tickets, which are valid on booked train only,  can be bought from any train company (linked from National Rail) or from resellers such as Trainline, Raileasy or RedSpottedHankie - although resellers can add extra fees. Coach journeys can be bought from National Express.  Cheaper coach fares for inter-city routes are available from Megabus who also operate Megatrain. 

If you are staying in London then the economical way to get around is to purchase a travel card. Do not buy individual tickets as this will eat into your budget. The other alternative is to buy an Oystercard - an electonic cash card for travel which has a daily cap on the amount you will spend on travel. This cap is the same as a day travelcard so costs work out about the same but is a bit more flexible. Its what the local use.    

If you are eligible for a Young Person Railcard (aged 16-24 years old) or Senior Railcard this can give a discount of up to 1/3rd on many train fares. 

For travel around a local area, there is a wide variety of Day Saver, Rover and Ranger tickets offered by local bus and train operators. 

The BritRail Pass is also a viable option for the non UK resident The BritRail Pass allows unlimited rail travel throughout the UK Rail Network and is valid on all rail operating companies. This railpass allows the traveler to travel for a set period of time for a set price. You can find more information about the various BritRail Passes available at BritRailBritain On Track. Britain is part of Interrail and this may be an option for younger rail travels coming from continental Europe as it may work out to be mlore economical than a BritRail Pass.  

London on a budget?

It's difficult on the accommodation and dining fronts. Prices in the capital city can be nearly double what you'd pay for the same item in, say, Manchester or Newcastle (e.g. a pint of lager in a well known pub chain in Newcastle: £1.75, Manchester: £1.99, in London £3.25).  In fact, London is now the most expensive city in the world in which to live.  A fair number of museums are free entry and you do not have to pay to marvel at the architecture and history, however, so there is a plus side. Expect to pay £4.60 for a Zone 1&2 Day Pass for the Tube and around £120 per room per night for a 3* hotel.

Some UK hotel chains do cheap deals (£19 -£29 plus) usually they have to be booked ahead (often 4 weeks or more) and may have a short window in which to book. These prices tend to be for outside London although they will have deals for London.  But check any extra charges such as breakfast which tends not to be included in the room rate. If you are on a budget a bed and breakfast may work out to be a better buy. Two of the more well known names are Travelodge  www.travelodge.co.uk and Premier Inn www.premierinn.com .

Staying in a bed and breakfast could work out to be more reasonable and give a more personal experience. Check out the hotels section of each city or area you wish to vist for reviews and costings. 

The youth hostels in London typically charge £35-£50 per night, though this generally includes breakfast too.
There's an extensive youth hostel network across the UK. Rooms start from around £12 per person per night. Campsites are available, but these tend to cater more for caravans than tents and facilities are more basic than you would find in mainland Europe. However, a night will cost anywhere between £4 and £15.

Some farmers will offer their fallow fields and use of outhouse facilities for camping, and the charges are usually nominal, you may even get free food (a loaf of freshly baked bread, some eggs, freshly harvested vegetables, ice cream and so on) if you "muck in" around the farm!

A number of universities also offer their halls of residence as accommodation over vacation period. The rate is usually quite cheap, expect to pay between £10 and £30 per night. B&Bs (Bed & Breakfasts) also exist, £30-40 per night is usual in rural locations, with prices climbing slightly in the cities. 

Places to visit 

If you plan on visiting a lot of stately homes, country houses or castles then you could buy a 14-day pass for the National Trust, who now run a fair proportion of these properties in England. A family pass is £46 and a pass for 2 people is £40. This entitles you to free entry and parking at all National Trust venues. 

Be warned, however, the major tourist sites (such as Windsor, Stonehenge, Tower of London, Edinburgh Castle, York Minster, Hadrian's Wall) are not part of the National Trust. Check whether your sightseeing venues are part of the group before you purchase this pass. Other organisations operating major tourist sites, such as National Trust for Scotland, English Heritage, Historic Scotland and CADW (Welsh Heritage) may offer similar passes.  

That aside, the National Trust family pass will save you money if you visit 3 places or more during that 14 days. If you are visiting for a longer period, and have a bank account in the UK, then you might want to join the annual membership via direct debit (£33 per person or £60 for a family). Visitors from the USA can join an affiliate organisation there which also joins you into the UK National Trust. 

There are lots of great places run by the National Trust, but they're usually rather quieter houses or gardens by themselves, with little in the way of "edutainment" (not many interactive displays, videos, theme parks etc) but some of them are sites of significant historical interest such as where King Charles hid from the roundheads in an oak tree.