Once again, my 11yo son has grown out of the snow boots he wore a grand total of 3 times last year. I need to get him some new ones in case this turns out to be a snow year, but I don't want to break the bank. He's also very sensitive about what he wears - if the material is too stiff or if the boots are hard to get on, forget it. Let me know if you have any favorite brands!
Have you considered getting a pair of waterproof hiking boots he can wear year round? For winter a thick pair of socks and a pair of gators might do the trick to make sure the boots are warm and he doesn't get snow down his ankles. I believe Ascent Outdoors in Ballard has kids gear and Outdoor Research makes low gators for kids. If he's only wearing them occasionally, might get more mileage there.
Kamik is a more traditional winter boot brand I'd recommend with great kids products and excellent sustainability standards. If you want a winter specific boot, rather than an all season waterproof hiker. I have a pair of their women's ducks and it's all I wear from November to March, including on snowshoe trips in the mountains.
For whatever reason, boys boots are harder than girls, I’ve found. Good luck. The brands mentioned above are great, and we’ve also found a great deal on last season’s Columbia boots from REI Garage. This is a case where I’d scour the internet for a deal rather than buying local. And if he’s not too old to complain, size up as much as possible.