$19 expensive ????? They last at least a few years unlike even Anker .
One time I saw Belkin 2.1A power adapters for less than $2 each. I saw them available online at Fry's Electronics and they were supposedly in stock. I had to ask an associate to look it up and they were abled in the stockroom but they came in bags, where I got 5. They've been working great. I think I got some Anker USB-A adapter at $25 for a 3-pack. I've never purchased an Apple power adapter separately although once I just got one separately with credit card points.
These things are actually quite cheap to make but there can be a huge markup - especially with Apple. I've never bought an Apple one but have used what came in the box. iPhones no longer come with power adapters, but Macs and iPads still do.