I haven't tried a Walmart warranty yet but it doesn't sound like a good idea if they don't even know the details.
I opted for a Squaretrade warranty on my Galaxy S III. They have 30% off codes on Tuesdays so it was a good deal. They have different tiers of coverage (one is up to $199 in coverage which would be what you'd want) but I'm not sure how much it costs. You should check it out.
I usually pass on these types of warranties but phones are getting pretty expensive these days!
Sent from my Galaxy S III
Castrol EDGE 5W-30 is my drug of choice.
Primary: iPhone 6 64GB, Galaxy Note 3, Lumia 635: 5 lines, 3x $5 Android web, 1x $2.99 T-Zones, corp discount + $10/mo loyalty discount = $93/mo tax inclusive
Secondary: iPhone 4S & LG Ultimate 2: TracFone (Verizon)
Tablet: iPad Mini Retina w/ T-Mobile 4G LTE ($10/mo for 5GB with hotspot)