If a data-only package sounds a bit restrictive, consider this: a lot of people nowadays don't use the cellular service on their phone as much as data, and if the data package is "good enough", it'd allow people to make calls through VoIP services like Google Hangouts and Skype. Ultimately, if some customers don't use cellular too often and are willing to forgo a real phone number (unless one is opted for through a VoIP service), it could actually prove cheaper to go this route.
On the topic of price, the leaked document shows 6 package tiers, with the smallest being a meager 2GB. That one will cost $20, which isn't too shabby if your requirements are quite low. As you'd expect, the value begins to increase as you work your way up to the highest tiers. Paying $35/month, for example, triples the data, to 6GB, and for $15 more ($50), you could get 10GB.
If you're seriously data-hungry, there are three more packages to choose from: $65 (14GB), $80 (18GB), and $95 (22GB).
There are just a couple of caveats to be aware of with these plans. For starters, a GSM device is required, and if you're a BlackBerry user, you'll need to own a BlackBerry 10 device (including the Priv). It should also be worth noting that these plans are not eligible for the $10 Automatic Mobile Internet discount.
For data warriors, these plans could prove to be a boon, because who wants to pay for something they're not using?