Update: Brightspot is official.
Already confused by the myriad of prepaid carriers out there? Well, Target thinks there should be one more. After @evleaks outed the name and pricing last night, more details have emerged. Target's prepaid service will run on the T-Mobile network and is launching October 6th online and in Target stores.
Pricing starts at $35 per month for unlimited talk and text, but no mobile data. For $50 you get "unlimited" data, including 1GB of 4G. Keeping in mind T-Mobile's loose definition of 4G, this does include both HSPA+ and LTE. Go over that 1GB allotment, though, and it's down to 2G speeds. For $65 per month you can bump the data up to 4GB of 4G with the same speed hit if you go over.
Compared to T-Mobile's regular plans, the Brightspot rates are a moderate savings. T-Mobile proper is $50 for 500MB of 4G and $60 for 2.5GB. Brightspot is a slightly better deal if you figure in the $25 Target gift card you get every six months with the service and 5% savings if you pay with Target's in-house Red Card.
Brightspot will be offering a few devices for sale directly including the Galaxy S3, LG Optimus F3, and LG Optimus F6. Pricing isn't available for the phones yet, but expect at least a few hundred bucks. You can also bring your own unlocked GSM phone... like an as-yet unannounced Nexus device, for example.