Even though Ruby is a mini she still manages to wreck everything. We got her a kong which has lumps out of it though has lasted, and also 100 tennis balls from Ebay for a tenner! For taking out on walks, as she doesn't get must chance to chew them up, just squidge them into a non-ball like shape rendering them useless.
I am cautious about them as they smell quite strongly - someone told me to be careful of dogs with tennis balls because of the chemicals in the materials they're made from, but I keep an eye on her and make sure she doesn't chew on them too much, and hopefully just fetches them to us!
I did buy her a plastic ball with a rubber casing on it for christmas, the ball inside rattles and she loves it! I got her that from TKMaxx and it was about £6.99. It has lasted well so far, it's sort of like thick rubber strips across a heavy plastic ball, the rubber is like kong material and heavy duty. She has chewed a few little bits off but no more so than sh has her kong and that's still serviceable.
It's a constant hunt!
My cousin uses plastic pop bottles/milk cartons for her dogs (a Wire haired German Pointer and a Rottie/Boxer cross) to fetch and chew. I think they like the noise, but it'd drive me bonkers. So would the bits of plastic under my feet!
Good luck on the search. It seems never ending! The hunt for the ultimate doodle toy. I think there's one for Dragon's Den if anyone is feeling inventive...
Love from Luce xxx