Thanks to Darla for this Frugal Baby Tip!
I found a neat container at Walmart for this purpose and we used it on our camping trip. It looks like a tiny diaper bucket. It's the container made to hold the 85 load bag of Tide. This thing closes pretty tight. The only drawback has been its size. I have 2 in diapers, and the bucket holds about a day's worth of diapers.
I managed to cram 12 Motherease one size into it. If you're not planning to wash you'll need something bigger, but maybe you could use it for just the poopy ones.
P.S. it was about $4.00 - I use one to soak my reusable pads in. It's perfect for that.