U can order your lens from one of those sites online lens express like visiondirect.com where u can get them at reasonable prices and have it delivered straight to your door.. Disposables, you can order 30 pairs or up to 90 pairs per box so you always have a constant supply. The cost can vary but after your first order, you are usually sent promotion codes for added 10-15% discounts on future orders. U will need to get a prescription from an eye care specialist prior to buying lens since it is unlawful for any company to sell you lens without one.
I wont say the disposables are necessarily cleaner than extended wear and you still need to take proper care.