Welcome to the forum! I'm an adult hamster owner - no kids, so I can't even claim she's for them. Instead, she's the rather spoiled child of two twenty-somethings!
To be fair, I think they're actually pretty good pets for working professionals - they are awake when you're at home, asleep when you're at work, far lower maintenance than a dog and can be left for a night without chaos ensuing... that said, I've never quite worked out why they took off as a children's pet, given that they tend to wake up as the kids are going to bed!
Anyway, probably the best starting advice is to buy a cage that's big enough. They don't have to be expensive - Zooplus do three cages that are large enough for £33-70 inc. P&P depending on model (Alaska / Barney / Alexander) which is cheaper than many of the tiny bits of plastic shite that Pets at Home sell.
Hamster Cages | great selection at zooplus
The wheel must be large enough so your ham doesn't have to bend its back or neck at all to run, even when fully grown, else it will develop spinal problems. Often something around the 12" mark is necessary by the time they're full grown (Trixie / Karlie Wonderland are two of the more popular ones)
Fitch is the bedding that many on here rave about - and it's very cost effective
https://www.fitchrecycling.co.uk/fit...bale-20kg.html
Harry Hamster is often mentioned as the best food, nutrition wise.
I say this now because it's best to buy what's necessary early on rather than buying something inadequate and having to replace it later on. I'm sure you'll find that the received wisdom on hamster keeping has changed a great deal in the last 30 years - but they are such cute little creatures
