[Update Sep. 12 2013: They are currently charge-on-delivery only] For US customers only: This is the cheapest storefront for the EcareMD / Troy Pharmacy company we have found with, for example, 120 tramadol for $145. They are a long-established company and the prescriptions are filled by a US bricks and mortar pharmacy. They no longer offer a credit card payment option unfortunately, all payments are charge-on-delivery (COD).
They will not ship tramadol to states that control tramadol, which at the moment is: Arkansas, Tennessee, Illinois, New Mexico, Ohio, West Virginia, Kentucky, Wyoming, Mississippi, North Dakota, and Oklahoma. If you live in those states then eHealthRx.com might be an option for you, it is based offshore but run by the same company as RxMegastore.com.