Morrision's are doing 5 henry hoover bags for £2.99. I reckon i get through that in a year! a vacuum cleaner with some low running costs! This dosen't appear to be a promotion, it's just the price of them, which i personnally think is quite reasonable, to find them instore can be a bit tricky, in my store in ipswich they're located in the far corner by the toilet/kitchen roll. I looked for some at Asda and they seemed to stock everything but henry bags!
Also if you want to save even more money! don't use a bag! you can run a henry without one and just fill the bucket them tip it in the bin, slightly messy job to say the least! but useful for sucking up brick rubble or things that are a bit big for the bag.