Our Beauty Editor says if you only take advantage of one deal today, it should be this.  

By Patricia Shannon
Each product we feature has been independently selected and reviewed by our editorial team. If you make a purchase using the links included, we may earn commission.
Stila Stay All Day Waterproof Eyeliner
Credit: Amazon

You've heard us talk about this eyeliner before (see here and here). It's just that good. It creates a perfect line in one, effortless swipe (no pulling at your eyelid required). With Stila Stay All Day Waterproof Liquid Eye Liner, you barely need to dust the brush over your lash line for perfectly intense color. It was a game changer for me, so much so that it's one of the rare products I buy on the regular—even with all the free products that come across my desk. It's good enough to warrant the $22 buy, but that doesn't mean I wasn't jumping for joy when I found out it's one of Amazon's Prime Day Deals. Today you can get my favorite eyeliner (of all time!) for just $15. That's 30 percent off it's normal price. Run, people! Don't walk.

BUY IT: $15; amazon.com

If you aren't convinced already, here are a few more reasons you need to add this little liner to your cart.

It's in it for the long haul. One drawback I've found with liquid liner pens is that they tend to dry up a bit more quickly than pencils. Not so with Stila's version. With nearly daily use this liner typically lasts me around 3 to 4 months—bonus points for never going dull.

It's fully customizable. Do you keep it classic with a subtle, less-is-more approach? Or do you like to bring a little extra pizzazz with winged liner? Wherever your preferences fall in the eyeliner universe, this liquid liner has you covered. The super fine tip is ideal for tightlining or painting on a slim line. But, if you're looking for a fuller look, tilt the pen horizontally as you sweep it across your lid.

It's going to make you an eyeliner pro. Think you'll never quite master the art of eyeliner? Think again. Liquid liners can be tricky, but this one is the exception. It's by far the most user-friendly version I've ever tried (including the pizza-cutter-like varieties that popped on the scene a few years ago). Be prepared for expertly symmetrical liner every time.

WATCH: How to Apply Eyeliner

Jump on this Amazon Prime Day Deal before it sells out and do let us know how much you like it. We're not even giving you the option to do anything but go bananas for this one. As we said, it's just that good.