I have found some bags that are great addition to PSK they hold 1 litre have a strong zip seal and are self-standing.
Pour & store made by Poly-lina in the UK, I found them in my local tesco store they are approx 240mm x 155mm feature a resealable airtight seal and have capacity levels printed on the side of bag. You get 8 for 99pence.

buzz

good find. do you have a link?

How compact do they fold too? would they fit in a PSK?

Yeah they fold flat, Zip closure sticks up a bit but this is minimal. They also seem really robust and are designed to store and freeze liquids. Once filled the bottom automatically opens out to make a stable base, no more struggleing with condoms for me ! <img src="images/graemlins/wink.gif" alt="" />

Sorry Woft cannot find a link. I live in the UK and they should be stocked by most Tesco supermarket stores here but that doesn't help you in SA. A web search for the company name only returns a postal address no url!
I will send another post if I get any more info.