I have just reduced a double quilt to the size of a pillow in a bag i got from Home Bargins you get 2 in a box and they were £1-99 i have had them a while but im sure you can still get them there, 1 bag is 100 x 70cm thats the one i used for the quilt and the other is 50 x 60cm and i have just put a fleece blanket 2 bath towels and 2 smaller towels in it its now about the size of the cushion on my sofa.
Tested it out with a few cushions in a cheap bin bag and it worked a treat! You can use it again and again on as many bags as you like. I tried vacuum bags from several places and they were all pretty poor after a couple of uses.
This thing should last forever. All you have to buy is new bin bags. I love the fact all I have to worry about is taking the button and a roll of bin bags and I'll be sorted for the way home - no more worrying about the vacuum bags working and being stuck in a field with huge cushions and clothes!
I think slightly better bin bags would work better, but they are still pence each, rather than pounds for a vacuum bag.
For the way home the deflate on the pump should work a treat
We got ours from Dunelm Mill, we can in the large size ( i think ) 2 adult sleeping bags and 4 pillows. And we use a hoover a small one brought from B & M for the van and to suck the air our of the bags.
We got the £29.99 set with 1 jumbo tote, the jumbo totes alone can cost around £20. The totes will take 2-3 sleeping bags plus clothes depending on how good a packer you are then its shrunk to almost nothing.
We bought a small cylinder vac around £12 from Asda to take with us to redo them and to hoover tent carpet when get mucky. You do find with these bags some you get are cheap and flimsy but the proper space bags are ace and well worth it and you get the free roll squeeze travel bags for suitcases as well as the rest for things in the house.