
I usually buy my paper and card from 'Paper mill' if you're clever you can really load your boxes and get some lovely quality paper. I also bought a 'Make your own Greetings cards' CD, not too expensive...about £10 I think? Which is better to print the inners on, saves it getting all smudged like I do with stamps and ink lol For Christmas I usually do a photo of the dogs and mount it on the front of the card. Makes it personal too...For everything else I tend to look at some of the weekly markets going on...for example in Liverpool they have a twice weekly market that has a couple of stalls selling all sorts of stuff...if you're careful about what you buy, you can get a bargain or two!
I also use E-bay, just do a search for Craft supplies, there are hundreds of things available. What I would say though, if you use E-bay and find something you like, check the price if you can, online, from a retailer and remember to include the postage and packing costs too!
With Hobbycraft they do tend to do 'specials' quite a lot...check the web site for offers before you go!(though last time I looked you couldn't buy on-line...don't know if that's changed much?)
Enjoy!