When talk of retail clinics first emerged, most assumed that their primary business would be cash-based. After all, if you're going to charge low prices, you might not want to take on the expense of collecting insurance reimbursement. But for many retail clinic operators, that's not how its shaping up. The most recent example comes from RediClinic, which has just announced that it will accept traditional Medicare coverage at its 46 U.S. locations. The company already has contracts in place with Medicare Advantage plans offered by Aetna, CIGNA, Humana and UnitedHealthcare. RediClinic is backed by AOL co-founder Steve Case, and is affiliated with Case's Revolution Health Group.