We did the gallon size ziplock storage bags for our DS5 last fall. It worked great! Like Memaw2Wm, I was able to put a full outfit (shorts, t-shirt, underwear, socks) into a bag. I zipped them nearly closed and stuck a straw in the little opening and sucked the air out! It worked great and DS liked just picking out a bag in the morning. This year, I will probably leave the socks out - most of the time he wanted to wear sandals. I'll just pack a few pairs of socks separately for when he needs them.
pdarrah