In an effort to reduce network saturation, Sprint has just announced they will have to cap data limits to 5GB for mobile hotspot usage on their smartphones. Previously, for $29.99 extra per month you could use your mobile phone's 3G or 4G connection as a mobile hotspot for all your devices, and the data was unlimited. That data will now be capped to a limit of 5GB per month, and will cost an additional $.05 per megabyte over that limit.

Interestingly, this new limit does not effect their tablets. Also, the unlimited data plans for their smartphones are calculated separately from the mobile hotspot usage, and these plans will remain unlimited. Here's a quote with a detailed breakdown,
“Sprint continues to offer unlimited data for phones in its Everything Data and Simply Everything plans,” a Sprint spokesperson told BGR in an emailed statement. “Mobile Hotspot data usage is calculated independent of a customer’s phone data usage. The mobile hotspot functionality on a phone enables other Wi-Fi enabled devices to connect to the Sprint network. Effective Oct. 2, Sprint is changing the optional $29.99 Mobile Hotspot add-on for phones. The new add-on has a monthly 5GB on-network data allowance for 3G or combined 3G/4G usage.”
Source: BGR