Welcome aboard. This is a great community with a ton of useful information to get you going. Just stay away from artisans and CNC'd korean boards and your wallet should be fine.
For your son, I would recommend something in the tkl or 68% range. If noise of the switch is an issue, stay away from mx blues or greens as they can be quite noisy. The redscarf that you are looking at is a great option in that you get the rough size of a 60% board, but still have the arrow cluster which I use often. One very good option for getting a very inexpensive but very usable board is the
Magicforce 68. This one uses cherry mx black clones which are a moderately stiff linear switch and may be a very good place to start. If you want to spend a little more, the board can be purchased with Gateron or Cherry switches. The gateron browns might be a good way to go and can be had for about $60. The layout of this is pretty good and the build quality is as well. The stock keycaps leave a lot to be desired, but that is usually the case with most stock boards. A cheap set of pbt doubleshots would take the feeling of the board much higher. Something like this
Balck and red set. The Magicforce is also nice in that it uses standard sized keycaps.
I hope this helps a little and gets you looking at some different options.