When you are working on a budget, treating yourself to the latest fashions of the season is rarely going to be an option, but if you're smart, you can still get yourself a brand new wardrobe full of clothes, while at the same time making some money off your old goods.
My first port of call is always the end of season sales. You can get some fantastic bargains, with most shops reducing their prices by as much as 70%.
Charity shops are also a great place. Don't be snooty about second hand clothes; I've found some real hidden gems in charity shops, including a sheep skin coat, and a red leather jacket for £10. You can also drop off any unwanted items while you're there, helping yourself, and those in need.
One man's trash is another man's treasure. With car boot sales you cannot only find some good designer deals, but also sell your own clothes and accessories that you no longer want. At the Battersea Boot Sale you can find some serious second-hand dealers, or book your own pitch for £20-£50. If you're feeling lucky, you could also turn up on the day and see if there are any vacancies for £10.
Capital Car Boot is the place to go for retro and kitsch fashions. Also because you are in central London, buyers are willing to spend more money on any quality items you may be selling. Booking a table is between £5-£35.
You get what you give. Take in quality items and you could get a reasonable price for them. Bang Bang in Googe Street will pay you up to 30% of the original price, and Strut, 25%. The Dresser at Marble Arch will give you 50% of the sale on your item if it sells within eight weeks.
There are some neat swap shops around London where you can clean out your wardrobe and refill it all in one go. Mrs. Bear's Swap Shop, for example classifies its stock in two ways: red for high street, and blue for designer. You get red and blue stamps for whichever you bring in and can then spend them like vouchers. The Grafton Clothing Exchange is an informal swap party held at their Kentish Town Pub, monthly on Saturdays.