MrPeanut,
I really enjoyed the three tickling story collections from Bad Penny; each one had at least one great story. "Severin" seems to be the most prolific tickle story author on Amazon. I haven't read much of their stuff at all so far, but "The Tickling of a Lady Executive" was great (enough to make me want to check out more from this author). And "The Sleuth Who Tickled Her Clients' Feet" by Lucy Horn and Anton Romano was really good too. If it's helpful at all, in general I've found the tickling stories to be far superior to the foot fetish stories on Amazon. There is definitely some tickling material worth dropping a few bucks for. Just remember that Kindle downloads do show up in your Amazon purchase history, and will tweak the algorithm for things that get recommended from Amazon.