While prepaid service in the US is typically associated with lower-end phones and a shortage of features, in Europe it's more of the norm, with data-heavy plans and spendy, unsubsidized phones built for VoIP. Now Walmart is getting the exclusive on a new $30 a month '4G' prepaid plan on T-Mobile, which includes unlimited data (speed capped after 5GB), unlimited text, and a mere 100 minutes of talk. Walmart will also start offering a contract-free '4G' T-Mobile handset, and while we're not sure which one they've picked (obviously something like the Galaxy S II is an unlikely candidate), there isn't really a stinker in T-Mobile's current crop of HSPA+, so that's reassuring. We reached out to Walmart about what phone they're getting, and we'll update you as soon as we find out.