Ditch those prepackaged popcorn bags. Nordic Ware's 12-cup microwave popcorn popper makes perfect popcorn every time, with or without oil. It's basically an unbreakable, high-temperature-friendly bowl with a lid, which produces popcorn similar to what you'd get from a hot-air popper appliance without having to spend the money on one.

I found this Amazon review super helpful in terms of popping time and suggested popcorn to use with it:

Once you get the timing right, for me it's 2:10, figure out you need to add the oil on top of the unpopped kernels and shake them around a bit, and remember to add the salt before popping, you wind up with perfect popcorn with almost no mess.

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UPDATE 2: Found what I think is THE BEST POPCORN for this popper. Great Northern Popcorn, 4-Ounce Portion Packs (Pack of 24) tastes lots better than anything else I've tried. The only problem is the 4-ounce pack overflows the bowl and my next order, and there will be a next order, will be for the 2.5 oz packs.

Reddit user /u/spoonweezy also offers a good tip:

I use a brown paper lunch bag. 1/3 cup kernels, roll the top of the bag, 2 minutes on high. Perfect every time.

Get the popper for $9 on Amazon.