I bought this little basket at the "everything's a dollar" store for, you guessed it, $1. It has a nice flat bottom and is pretty solid. The bottom (table top) is 11.5x7 and it is 6" tall. Weighs only 5 oz.
If you pack it full of stuff, then it's like it's not even there in your pack. I put my quilt (orange stuffsack) and poncho/tarp in there as an example, but I could have squeezed a lot more in it. You could proabbly cut those little handle things off if you wanted. Who knows, coudl come in handy for carrying something, too.
If you did use one of these, I would run a medium sandpaper of the edges of the top lip. They area little
This isn't a perfect solution, but it works, is super cheap, and super light. honestly the only
downsize is that it doesn't fold up. Again, if you fill it up good, then that aspect is less of an issue. It would definitely fit in even the smallest packs
If you liked it, you could go buy a bunch and think of them as somewhat disposable.