£25-£35 is probably the most common price range. Both of mine were £25. You don't need any cleaning materials or overpriced solutions full of chemicals - the best aftercare is sea salt soaks. And salt is pretty cheap. ;D 1/4teaspoon of salt in a mug of hot water, soak the piercing in it (using a shot glass is a good idea) for 5-10 minutes, once or twice a day.
Barbells are much more suitable than rings - don't get it done with a ring. It'll stick out a lot, get caught more and move around more (which will irritate the piercing). Contrary to popular belief, you shouldn't be moving or turning the jewellery, it disrupts the healing piercing and doesn't help cleaning/healing.
The longer you wait for swimming the better - but if you absolutely have to swim, try and put it off for at least a few weeks, and make sure you rinse it well with plain water or a sea salt soak after each time you swim. A big waterproof plaster might help, but it's doubtful you'll find one big enough to cover it completely and strong enough to stick on for the swimming without actually stop it getting wet, heh.