If you hop on over to Best Buy, you'll find that they have a doorbuster deal on the Samsung smartphone, giving you the chance to buy it for exactly zero dollars and zero cents. This deal, which is being offered both online and in brick-and-mortar stores, is applicable to a broad range of carriers too. Whether you're rocking Verizon, Sprint, or AT&T, you'll have the chance to get the Galaxy S4 for free on a two-year contract. This is valid both for new activations and for contract renewals. So, the contract is the first catch. The second catch is that you're still on the hook for the activation fee, which is about $35. Given that the regular contract price for the 16GB SGS4 is still $250, you're still getting a pretty great deal on a pretty great phone. The unlocked version sells for $799.99, by comparison. The free Galaxy S4 deal starts today and runs through to Saturday.