Today in iLounge Deals you can pick up the DrinkMate Breathalyzer for only $31.99 — 20% off the regular price. This handy little device lets you check your blood alcohol content (BAC) on the go, and it’s ultra-portable at less than two inches long so you can slip it into your pocket or hook it onto your key ring. It’s powered by your iPhone’s lightning port so that you don’t need to worry about batteries, and can measure…