With some searching and yard sailing you can surely find a miter box and saw for
much, much less.
The quality of that model is fine, though. They were made the same from the
1950’s through the late 1970’s. Just changed to a cheap stick on label.
If and when you buy one, make sure you get all the little attachment parts with
it. Otherwise you’ll have to fabricate your own because they’ll cost more than
the box you’re looking at in the end — if you can find them at all.
They spelled it the British way, “mitre”, as a marketing idea I think, from the
outset in the 19th Century - and it stuck.
Google should have led you to: