Depends where you are and budgets. As mentioned certain auction sites are pretty good to get a bargain or two, likewise you can pick them up from most book shops in the UK, occassionally you find them at Car boots. What I can do is if I find any I'll let you know (if you can provide a list youre after, let you know what I paid and the postage to where you are.) Be wary though if youre in the states it will cost quite a bit, but if in the UK it should be about £5 if prepared to take a week to get there.
A good website is my own, its updated quite a bit and I will be adding the tour dates shortly for the September release of Shield of Thunder.