Your breast implant choices may seem limited, since at present only saline-filled implants are available to women undergoing cosmetic breast augmentation and since only two manufacturers - Inamed Aesthetics and Mentor Corporation, both of Santa Barbara, Calif. - are FDA-approved to supply them. But the range of sizes and variables designed to accommodate different body types and desired outcomes presents a number of questions when it comes to purchasing and stocking implants. The possible return of silicone gel-filled implants could also complicate the process. Here's advice on buying implants with economy and efficiency in mind.