I don't remember what I paid for my last MAP gas (which I probably purchased earlier this year. But I do know where I got it from. I am very fortunate to have a small independent hardware shop about ten minutes walk from here (or just five on the bike). My nearest big name hardware store is a good ten minutes drive away.
I try to make a point of buying my small 'DIY' needs there including MAP gas, the odd pot of varnish or paint, wood glue, hacksaw blades etc. He's generally about the same price as B&Q (sometimes a wee bit more expensive and sometimes even a bit cheaper) but he's often a tad cheaper than our local Robert Dyas (who used to be very good many years ago)
He stocks a range of product/brands that I often cannot get in the big stores and he is pretty knowledgeable about what he's got (he advised me to use Gorilla Glue when I had some plywood delaminate for instance). He's open to feedback about what he's sold (and will make changes accordingly) and he's willing to find out how much something new will cost and will get it in if I'm still interested – e.g. he listens to his customers!.
Of course I purchase all of my specialist (metal torturing) tools online these days and any other major purchase gets well and truly investigated on the Web before I spend my pennies. But for my smaller general needs I try to give him my business and (being somewhat dis-organised) I usually manage to run "out-of-stock" of something crucial just before a job (or during it) – like running out of gas for instance. So it's real handy to be able to just walk up and get it locally. I'd certainly miss the convenience and choice I get from him if he shut up shop.
So, If you are lucky enough to have a great local HW shop near you (as I am) then perhaps the price is not the only consideration.
Regards,
IanT