The official currency and legal tender of Mexico is the Mexican peso.
Mexico is relatively good value country to visit from a British tourist point of view. Prices are around half what you may find in London. Here is a little snapshot of prices you may find if you were travelling to Mexico City:
A meal in a reasonable local restaurant may cost $150.00 (about £5.00) and even a 3 course meal in a mid priced restaurant would only set you back $350.00 (£12.50). A pint of local beer will cost around $40.00 (£1.45), a coffee slightly more, a coke is around the equivalent of 65p and a bottle of water 50p.
If you are self-catering, milk is 82p a litre, a loaf of bread is £1.20, 12 eggs £1.20. 1kg of chicken fillets for your Fajitas would cost about £3.70.
Local transport is amazingly cheap. A one way ticket may cost as little as 25p. Compare that to the £2.60 in London! A taxi start price is 80p and costs 24p per kilometre, or 38p per mile. That means a 5 mile taxi ride is less than 3 quid.
Car hire for a week can start from £85.00 for a small car up to £500 for a luxury car. Petrol is 80p per litre.
If you are booking independently then accommodation can be very reasonable. We found lots of hotel rooms for as little £40 a week but it has to be said the reviews were not very good, as low as 3/10 in some cases. We found an Hotel with good reviews for only £95.00 per week for 2 people in March. You would have trouble finding a room in London for one night at that price!