If you have a look on the “Let’s see your cages” thread there will be other ideas too
. Also just to add - lots of things can be made rather than bought. Someone on here made their own labyrinth house out of cardboard - and a shoebox house can be good too or tissue boxes for hidey places etc. Also check out the video - 10 toilet roll toys for Hamsters by Erin’s hamsters - there’s even a hammock made out of toilet roll tubes. The only safe string is sisal string or rope though, if hanging things.