I have the aldi ones two packs of six bought a couple of years ago when they are around a tener a pack, both blue one with holes one without and we make them up in a chequered pattern
What exactly do you use them for, sorry if I'm being a bit dull. I see them being mentioned here all the time but can't really see a use for them.
I don't like to miss an opportunity to spend money on more gear! :-)
Brought mine from Seaflo Caravan accessories on Ebay. If you live close to Oldhill, Halesowen in West Midlands they have a very big warehouse where the cost is cheaper than Ebay if brought over the counter you save on postage.
They are excellent quality a little thicker than Aldi ones. They come in packs of 6 as well and storage bag if you look at deals.