This guy replaced his own trunk for $687
It was off of an IIHS crash vehicle and matched perfectly.
I doubt blending is necessary, but it probably depends on the paint color and the conditions the paint has been exposed to for the year you have had the car (if there has been minimal sun exposure it might be ok). It also depends on how picky you are.
Body shops frequently use salvaged parts so it's a smart way to go if you can find what you need (which is clearly a matter of luck).
The advantage of this route is that there is no record of the incident (no diminished value). I don't think anything would go on the vehicle record if it never visits a shop and the claim is a cash payment to the injured party (presumably that's what the poster above did - made a claim of $687 to his insurance company which then extracted it from the at-fault party). (Note that if there is a lien on the vehicle this may not be allowed as there is a lienholder interest...but if you own the car outright it is pretty uncomplicated.)