Well, as with anything, there are a lot of things that factor into price. Grinders are not special in that regard. You could pay more for brand name; for where it’s made (US, Germany, Japan vs China, Vietnam, Mexico); more options, like more granular controls or automation; better quality materials, like better, quieter, or longer-life motors and plates; design aesthetics; glass and metals vs plastics; whatever. Some of these could affect grind consistency, and many won’t. I honestly don’t know how you’d tell outside of reviews on coffee-related sites. In general, I’d say anything made in Japan is probably still a safe bet; although most quality grinder companies seem to be Italian, there are still fewer sketchy companies in Japan than anywhere else.

I’ve never heard of Melita, but I’m not exactly an expert. Companies have long known giving their company a name similar to a name that sounds live it comes from a country with a reputation for quality it a field will increase sales. Melita might sound Japanese, but be actually made in China, or you might hear an French-sounding name used by a cheap American wine maker. Just review the company, see where it’s made, see if you can find reviews.

Incidentally, tyere are excellent quality Chinese companies, but few that are alse cheap. This is true for any country; you get what you pay for. I have a machined aluminum, high-power laser made in China. It is very high quality; it was not inexpensive. So if your $15 grinder is refurbished, or lightly used, and it’s far more expensive new, then sure. Why not? It’s not much of a risk at that cost. But if that’s the cost new, then hard no. I’d not risk money on any grinder less than $70 new, and $100 if you can stretch that. There’s only so little quality materials cost. Like I said, refurbished is a different matter, and can bring the cost down.

I will add a caution about used grinders, though. The nature of grinders is such that it’s easy to use a grinder in such a way as to damage the grinding plates. You never want metal-on-metal grinding, for obvious reasons, and most burr grinders will let you set the grind so that the plates are touching. If the previous owner misused the grinder, you could get a damaged one and not be able to tell unless you take it apart and inspect at the plates. If the company did a refurbish, they probably checked it (you’d hope). Do not accept Amazon refurished; they test products function and superficially clean them, and little more. Fine for maybe a Wifi router, but I wouldn’t accept an Amazon-refurbished grinder.