Home depot used to carry two different sizes of pop up round canvas bags for leaves or garbage. Don't know if they still do or not.
Ray

Most party supply stores also carry big bags for balloons. I've used this before without any problems.

Magicjody ,
I use the same mesh pop-up laundry baskets that spellbinder uses , they are ideal , very light and of course collapse into small discs when all the balloons are finished . They take up little if any space , they also come in a variety of colours . The ones I use are multi-coloured...i also cut a stencil out with my name on it and some stars and sprayed them onto the mesh , they advertise my name while adding a splash of colour to my show , as I place them on either side of my backdrop . Hope this helps!!.
Magically yours
John .