Make your own sandwiches!
The cheapest option would be to buy food from a local supermarket (there is a Sainsbury's in Cromwell Road; a Safeway in High Street Kensington and in King's Road; a Waitrose in Gloucester Road and in King's Road; and a huge Tesco on the corner of Warwick Road and Cromwell Road, with an inexpensive cafe inside). Buy some cold cuts, cheese, fresh bread and go to a local park and have a feast in the nice weather. This would be about £6-£7 for two.

Typical Fastfood...
Otherwise MacDonalds, Burger King, KFC are the usual cheap, fast food options. There is always one in easy reach, wherever you are.

Other Restaurant Chains
Not falling under the fast-food category, but still part of a chain, are places like Pret A Manger and Wagamama. Pret A Manger sell sandwiches (freshly made on their premises daily), wraps, salads, sushi, fruit juices, pastries (and anything else they can come up with that proves popular). Pret is actually pretty pricey - the cheapest, plainest sandwiches cost about £2, so if you want to go the whole hog you might find yourself paying quite a bit for lunch! That's not too say that the food isn't delicious though! There is a Pret next to the tube station, in the arcade in High St. Kensington.

Wagamama restaurants serve Japanese-style and Far Eastern food in canteen-style restaurants. Seating space is plentiful and service is fast, so even if the restaurant is busy and you find yourself having to queue. My favourite is the filling Chicken Ramen dish for £6! There is a Wagamama in High St. Kensington, near Kensington Gardens.

Cafes and Cheap Restaurants
There are some cheap cafes, and one of the cheapest is the Holland Park Café (inside Illchester Place, London W8) one minute from the youth hostel. The Evening Standard declared this café as having the best atmosphere amongst park cafés in London. It is highly recommended, particularly in good weather. Meals are about £3, a cup of tea for 45p. Benjiy's (157 Earl's Court Road) serve huge breakfasts all day long with as much tea or coffee as you can drink for under £4. The Troubadour (265 Old Brompton Road, tel: 020 7370 1434) is one of the original coffee houses in London. My father swears by it and it used to be his second home at one point! Meals are around £4. Live music downstairs in the evenings. Bob Dylan made his first London appearance here and John Lennon also played here. The Picasso Café (King's Road) has good food at reasonable prices. Popular with the locals, and you can even see some celebrities here somtimes! Chelsea Farmers' Market (Sydney Street, off King's Road) has several restaurant and café places which charge reasonable prices. The Chelsea Kitchen (98 King's Road, tel: 020 7589 1330) has been going for many years and serves cheap and filling food.

Cafe Chains
There are also countless Starbucks, Costa Coffee, Coffee Republic, Cafe Nero and all those other chain cafes dotted around which serve varied coffee drinks and pastries at reasonable prices.