Sorry to add to the chorus, but to give a Hamster a good life is not cheap. You really do need a big cage & one with height too, they like climbing the bars & different levels.
As others have said, they need a big wheel. The ones that come with the cage are FAR too small.
They need a lot of interaction & stimulation as well, which isn't always easy as they're crepuscular (active dawn & dusk) & it doesn't make them the best pet for children.
They can be difficult for children to handle because they're small & fast.
They can be cantankerous little shits as well. We have been lucky with ours, but lots of friends haven't beeen.
I'm not even going to tell you how much the vets cost if they get sick.
We use the 'toilets', most of ours have wee'd in them & it really does cut down on the smell. We 'tidy' ours daily (remove obvious poop, change bedding in the little house, remove any uneaten food etc) and change the drinking water testing the flow. We do a full change of wood shavings every week & wipe the tray. About once a month it gets a full wash. Some people say they never do it because it stresses the Hamster out, ours have always loved it & love exploring their new layout & toys.
I don't resent a penny we spend on them, because they're part of the family & we love them, but to keep them healthy & happy is time consuming & not cheap. If you're not up for the hassle or expense then say 'No' to the child & put up with the whinging. Our last one died a few months ago & I really notice now just how much time they take. I miss having one, but I don't miss the cleaning & mess they make plus trying to make time to play with them at dawn & dusk & them not being awake when the kids want to fuss them etc. I might get an elephant next time, they can't be any more work & they won't spend all day plotting how to get under the bloody piano 😂