A medium sized bag the Black Knight BG-424 is an excellent value. It can hold all of your gear including your shoes, racquets and accessories.
BG-424 Racquet bag
Made of heavy-duty nylon, with extra cushioning built in, this versatile bag will do more than its name suggests. Its large vented compartment (71cm x 20cm) will hold up to 8 squash racquets or 12 badminton racquets. With fewer racquets the bag can easily hold the shoes and clothing necessary for a trip to the courts. Two zippered pockets can be used to store valuables and small accessories. A detachable padded shoulder strap is included.