There are many options out there to enhance your hamster's fun. Pet stores will have many choices for toys and wheels.
Your hamster definitely, if anything, needs a wheel. They can run up to eight miles in one night on these things! Make sure, if you have a dwarf hamster, that you don't get a wheel with rungs. These cause hurt hamster feet and possibly broken limbs.
Plastic toys are very popular. They come in almost every shape and form and can be bought at local pet stores.
You also might want to consider purchasing a hamster ball. While cleaning the cage, you can put the hamster in the ball and they can run around on the floor without getting lost. It works like a charm.
So, you don't have deep funds? Try homemade toys! You can come up with just about anything, just make sure it is nontoxic. Try a toilet paper roll. Hamsters love these and they're virtually free. Also, try using plastic water bottles as tubes. Cut the bottles with scissors very evenly. Stick one bottle slightly inside the other and tape them together. You can make long or short tunnels for crawling and climbing in.
This is a cheap toy to make, also. Cut the bottom of an egg carton so the bottom of it has 12 open holes. You can turn the carton upside down and stuff it with bedding and let your hamsters use it as a nest or a fun toy.