IFixit is generally good quality/value in my experience if it’s actually them and not some knockoff/drop shipper. Granted haven’t had a need to buy anything of theirs for years because the one I have keeps being great.
That kit is $40 on their site. Weird that it’s cheaper on Amazon in the first place.
They do, but I’ve also seen it the other way around, where the price on Amazon is the price on the manufacturers site plus shipping. Usually for more reputable/niche products. IFixit I would’ve thought would be big/popular enough to do that but I guess not.