I got this blind spot mirror on ebay for $7.44 with free shipping, and there are several sellers that offer them for around that price. I opted for the cheapest Buy It Now that I could find, which ended up with a 2 week wait for it to ship from Hong Kong... but whatever...
It is meant to mount on top of the stock side mirror and can be adjusted to remove blind spots:
The way that the mounting bracket was attached, it would have placed the mirror too far forward on the car, so I flipped the bracket to bring the mirror closer to the driver. It was pretty simple, I just used a screwdriver to pop the mirror out and there were two nuts inside and then I just turned the bracket around and put it back together:
There were holes in the sheetmetal already for the mounts and wiring for my stock mirror so I just put the bracket through one of those and screwed it into place
The mirror is completely adjustable and pivots just like a traditional side mirror, which made getting the right view very simple.
All that's left is to cut some coroplast to cover up the holes left by the stock mirror: