RingPlus is running another promo on Labor Day (Monday Sept. 7). They're calling it the Labor Day-D Event. From 8 AM to 9 PM PDT on Labor Day you can get an HTC Desire 510 on the RingPlus Diversity Plan and phone and plan are free (while supplies last).
Well, sort of free. The free phone is a loaner and there's a $50 deposit. You get the $50 back if you return the phone in working order. There's also shipping on the phone which varies by state but averages around $20.
Update 9/6: SAVE $12 OFF Shipping use Promo Code LD2015DD in cart.
The Diversity plan includes 300 minutes, 500 texts, and 300 MB of full speed 4G LTE data per month for free. Diversity requires that you carry a $5 minimum balance in your account at all times. As soon as activate the plan, your card will be charged $5 plus tax. After the initial $5, the plan is completely free as long as you never use more than 300 minutes, 500 texts or 300 MB in a month.
If you do use up all of your minutes, texts, or data you will be charged $4.99 for a package of 300 Min or 500 Texts, or 300 MB (whichever you went over). The $4.99 package of minutes, texts or data is valid for two months.
The Desire 510 (pictured above) runs Android 4.4 KitKat and has a Qualcomm Snapdragon 400 Quad-core processor, 4.7 inch 480 x 854 px screen, 4 GB internal memory, 1 GB RAM, 5 MP main and 1.3 Mp front facing cameras, a microSD card slot supporting up to 128 GB cards and a removable battery.
If you don't want the Desire, the Diversity plan will also be available 8 AM to 9 PM PDT on Labor Day to customers who purchase a different phone from the RingPlus Store or who supply their own Sprint compatible phone.
Source: RingPlus Discourse Forum