A prepaid version of the Samsung Galaxy S II is now available at Walmart courtesy T-Mobile. The device costs $299 and is available coupled with T-Mobile's Monthly4G "no annual contract" plan, which will set you back an additional $30 per month. The plan, announced last October, provides you with unlimited data (though only the first 5GB are available at up to 4G speeds), unlimited texts, and 100 minutes of talk time. The prepaid Galaxy S II is available now, so you can pick one up at your local Walmart — that is, if you don't opt for the newly discounted iPhone 4S instead while you're there.