To the OP. Best practice is not to buy crampons until you’ve had training on use of crampons, axe, avalanche awareness and general winter walking skills. You can get day courses relatively cheaply at Plas-y-Brenin, Glenmore Lodge or the Lakes.
All kinds of things can go wrong wearing crampons whilst looking at a stunning view over the edge of a mountain, not spotting a big slab sitting above you waiting to drop, or trying to self arrest without getting your crampon-ed feet out of the way…
A very good friend of mine who is a fully trained winter guide likes to point out that plenty of people die in the hills in winter just falling over their own crampons…
Oh and I wouldn’t buy cheap stuff, your life may depend on it one day. And given the nature of what we’re talking about, it’ll happen when you’re in a very cold place and miles from home…
That said, winter walking is so much more fun than summer…