Candle holders & bud vases

I'd look out for the cheaper charity shops - the ones supporting small local charities or community projects. The big ones (BHF, Cancer Research, Oxfam etc) tend to be more fussy about what they take, so you don't tend to find large quantities OR cheap items in them. But local ones tend to have loads of these kinds of things - and sometimes will even put stuff aside for you (the volunteer demographic usually guarantees they will be going starry-eyed over wedding plans!)