What a lovely kind man ,and so lucky an honest person found your purse ! If the local shop you were in knows him well,you could perhaps ask them if he comes in for something for himself ...i.e. wine (if so what) cigarettes if he smokes, as I believe they are quite expensive nowadays, a treat of something else for him or his dog if he has one and doesn't just walk others......a donation to a charity and a nice thank you card. Any small gesture would I am sure be a nice surprise for him and probably unexpected ! I have found various things in my time (a gold necklace with a '21' pendant on it, money, a video camera, a gold engraved pen ,,,handed them all in ,,,never received a thank you but at least I knew I had done the right thing !