I don't see any difference in quality. I'm not a die-hard Parelli follower, but I do like NH in general, and apply a lot of the groundwork principles when dealing with my own horse. I tend to lean towards Clinton Anderson's methods, but the same price tag argument can easily be made for his equipment.
I have a "bootleg carrot stick" (string with leather popper included at no extra cost...
)that I bought at Equine Affaire three years ago for under $10. The only reason I own it is beacuse I couldn't pass up the price (My dressage whip with baler twine tied to the end was doing a well enough job...). I can say that the concept is wonderful, the stick is a much better tool than my improvised version, but $60 (plus $20 for the string
)wonderful? Methinks not.
As long as you know what you're doing, and the tack/tool fits you and your horse and you correctly (by fit I mean both physically accomodating, appropriate to the situation, and appropriate to the level of training/expertise), it's a good tool.
For myself, I simply refuse to pay anything over $20 for a rope halter. The case can be made and argued for a saddle of higher price perhaps being of a generally higher quality, but a good rope halter is a rope halter. Why pay $60 for CA's when I can buy an equally serviceable halter at TSC for $12?
If I must have a brand name item (a truly rare occurrence; I think there have been a couple of eclipses, six blue moons, and a coon's age since the last time that happened
), my favorite word... eBay!