Emily, for what it's worth, I recently did a headshot session for a local dental practice. There were 6 people in total and they wanted one headshot of each and a staff (group) photograph. The setup was a neutral grey background and a 3-light arrangement. Once the lights were all set, it was assembly line mechanics, so the shoot went quite swiftly. Retouching was minimal (just stray hair and lint on garments: my policy in terms of retouching is very conservative: no skin smoothing, no slimming with the liquefy filter, and so forth: essentially, if it's been there longer than a week it stays there). I shot about 3-4 frames of each person and they got to pick one from an online gallery: that'd be the only one I'd retouch. I threw in the group photo for free.
Final price was $490 plus tax. (They did benefit from a 10% discount for being fellow members of the local chamber of commerce, so $441 plus tax.)
Something like this is not unlike what you'd be doing. If $1K is too much, you could lower it to somewhere betwixt $500 and $999. Three hundred dollars is just laughable, unless the photography is really mediocre (no, I'm not saying yours is so, as a matter of fact I've never seen your images).
I understand that you might feel for them or don't want to burn a bridge, or what have you, but if you get people used to paying peanuts, you're not only spitting on your own work and effort, but you train them to pay low fees, and the moment you need to up your rates, bye-bye clients.