Is there a restocking fee on the panasonic lumix zs 100 camera if ordered when there is non on display to try?

Yes, if you have the original complete packaging also.

Bought Sony Bluetooth headphones but change my mind, is it returnable? Have had it less than a week, paid cash and have receipt.

According to Best Buys website, the only items related to cameras that have a 15% restocking fee are: "DSLR Cameras and Lenses, Mirrorless Cameras and Lenses" Most cameras are either or now, and the Lumis ZS100 looks like it's a mirrorless camera so most likely you will have to pay their 15% restocking fee.

Sorry, I'm afraid I don't know.