We highly recommend Tic Tac wheels for degus, they need at least 12 inch so as to not arch their backs. They also sell great metal tunnels.

Pumice stones are good for gnawing on, as are coconut shells and safe wood types.

Degus need lots of wooden ledges/platforms in their cage, make sure there are no high gaps that they could fall through (eg if you're using a Liberta Explorer or similar cage make sure to use the mid section floor so that there's no potential fall from top to bottom)

​

Minipetz is a great website for toys   

​

Chinchilla Lady is another great one  

​

The Hay Experts are also fab