Super Evil Megacorp announced on Friday that Amazon will be sponsoring the Vainglory Autumn 2015 Season Finals in December. Part of that sponsorship is a limited deal in which players who play Vainglory through the Amazon App Store are rewarded with a free Celeste unlock and purchases of ICE made through Amazon will return 50% in Amazon Coins. At first, this deal doesn’t sound super impressive, until you realize what this means. This isn’t 50% more ICE, this is nearly twice as much ICE! (If you’re an iOS user, stick around! We have a solution for you).

How? Well it’s 50% back on every ICE purchase made with Amazon Coins, even ones made with the refunded Coins. For example, if I purchase $100 of ICE, I get back $50; if I use that $50 for more ICE, I get another $25 returned to me. Mathematically, this can be viewed as a pretty classic convergent sum:

$latex \sum_0^\infty \frac{1}{2a^{n}}=1a+\frac{1}{2a}+\frac{1}{4a}+\frac{1}{8a}+…=2a&s=3$

If you take a number, add half of that number to it, then add half of that half, and the half of that half forever, you’ll double the original number. In the case of this ICE deal, however, you’re not able to do this infinitely; once you can’t use any amounts smaller than $5, since the smallest ICE package is $5. What this results in is a simple formula:

$latex 2\cdot A – 5 = V&s=3$

Take the amount of money that you’re spending on ICE—let’s say $20, double it—so $40, and subtract $5—$35. That’s the value of ICE you’ll get assuming you spend your refunded Amazon Coins on more ICE. Note that you’ll be left 250 Amazon Coins every time, because the smallest package, $5, refunds 250 Coins.

But wait, there’s more!

Amazon also has a deal on bulk purchases of Amazon Coins. When you purchase the $50 & $100 packs, you get 20% off (so $40 and $80). That means you can spend $80 for 10,000 Amazon Coins, and get $195 worth of ICE; way more than double the value. Here’s what the final ICE-per-dollar values end up looking like:

(It’s also worth noting that you can get an $80 gift card for signing up for an Amazon Rewards Card; be careful with that though, as you’re signing up for a credit card that will have bearing on your credit score).

For the non-Android Users

You can still take part in this deal, you’ll just need to install an Android emulator on your computer like Andy, Bluestacks, or Xamarin, download the Amazon App Store, and then download Vainglory through it. I personally used Bluestacks to do this and the only issue I experienced was not being able to copy-and-paste information into the emulator.

NOTE: using an emulator in Vainglory matches is a ban-able offense, so restrict your emulator usage to out-of-game activities.

For the non-Amazon, Android Users, just reinstall Vainglory through the Amazon App Store to take advantage of this deal.

Personally, I took this opportunity to drop a little on the game knowing that the crazy amount of ICE I gathered will probably last me a couple of years.