As a relative newbie to this camper game, I bought a full Campingaz 907 bottle last year - I can't remember the cost but do remember being shocked at it (and also at the then advertised refill cost). That said, we've been using the Campingaz C206 cylinders (the sort where you puncture the top) for years and years in both a small stove and a light when camping and never really gave the cost a second thought. This thread prompted me to look at it and I now see that they contain a 190g of butane/propane mix and at todays Go Outdoor price, worked out that it would cost about £39 to buy the equivalent of a full 907 which now seems extortionate. Out of curiosity, I also looked at the cost of the 'tall' (and removable) cylinders used in our other camping stove which is the ubiquitous 12" square/3" tall jobbie and worked out that the 907 equivalent in those cylinders (227G of butane) would come in at around £23, again from Go Outdoors. Interestingly (in a nerdy way), you can also buy the same amount from Amazon for about £11 including shipping. We've got quite a few of both types stashed away from our camping days and I think we might start using them before turning on the Smev in the van again as it's only usually used for boiling the kettle.