This Ting offer is outside of their usual range. $25/mo for 30GB for a hardware hotspot on the Sprint network sounds pretty good. Sounds like they don't have the physical hotspot devices available quite yet, but they're doing a pre-order thing.
The only catch I see so far is that you need to have a standard Ting phone plan as a pre-condition. If you don't already have a Ting line, that would raise your effective monthly cost by at least $6 (Ting's basic line charge.)