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I guess it depends on what you consider spending a fortune but if you don't fancy an Ikea hack then zooplus has some good cages, the hamster heaven is a good enough size for a Russian (best used without the tubes & add ons) or the Barney is another good cage, the alaska is a good cheaper option but it is a little tall for a Russian so you have to take care with your set up to avoid falls.
There are various tank style cages too which can work well, don't have links handy right now though.