I've never had a problem with smell
I haven't used Boxo personally but I wouldn't expect it to smell of anything except faintly of cardboard maybe! If your Mom means urine smells - then that isn't a problem if you set up a cage right, have a good depth of bedding, and a litter tray with chinchilla bathing sand. Hammies are quite clean little things really and will use a litter tray to pee in (if you put it in the right place!) - the sand soaks up the pee and you just empty and clean out the potty/litter tray every 5 days or so. Their poops don't smell at all - they're like little hard black seeds and they eat them sometimes for extra vitamins (which is normal - they have two stomachs and can redigest things).
Another bedding alternative is Kaytee Clean n Cozy - I;m sure that doesn't smell of anything but it's a bit more expensive.
The only thing that might end up being smelly in a small place is a female Syrian hamster on heat (some people find it a bit too smelly some don't).
I would go with a male Syrian - Syrians are easier to toilet train (in my opinion!).
You wait to see where they choose to pee (usually a corner of the cage as a toilet) and put the potty/litter tray there. Our hammy actually covers it up with bedding if he thinks it's getting smelly!
Have you thought about cages/sizes/where a cage would go? A lot of people in the US make bin cages because there are very few cages a suitable size for a hamster (most sold are not big enough). Some people use glass tanks. There are a couple of good cages but they are $100 plus.