My chinchilla likes to run through tubes and chew on them, and from watching videos most of them do! But, it cost ridicolous prices to buy a small amount of tube from pet stores. My solution to solve this problem is to go to your local carpet store and ask them if they have any spare tubes from their carpets that you can have, they will normally be generous enough to give you a long tube for nothing they sometimes might ask for a small amount of money, but i gurantee you it is much cheaper than buying a tube from your local pet store. (If you do decide to go to your local carpet store be sure to take a saw with you incase the tube is to large to fit in your vehicle).
That's a very nice solution! Well if you like cadbury's drinking chocolate you can use the 500gram tin for a tube, it's aluminum so it's washable and non-eatable, all you have to do it open the bottom of the tin with a tin opener (?). Enjoy!
If you go to a local wood yard you can probably pick up some cheap offcuts of pine, a bit of imagination and a few tools and you will be making chin toys in no time.
I really like Aaron's suggestion. You could make some cute little tunnels with shaped cutouts for you chinnies to run in and out of. Would be super cute. You could even use them to for inside the cage as well