And the drops, they keep on comin'. Just 48 hours after T-Mobile USA reduced the financial barrier surrounding the Galaxy Tab to just $350 on contract, the suddenly boisterous US Cellular is doing 'em one better. The carrier has just lowered the price of a shiny new 7-inch Tab to just $199.99 on a two-year data agreement, with the only major caveat being that consumers will have to opt for the pricier 5GB / month plan. That'll run you $54.99 per month with pay-as-you-go messaging, or $74.99 per month with an all-you-can-message plan. We still aren't tot