I'm graduating from Sanford in about a month. A couple of notes on themes I've seen in this thread:
1) I was able to leverage a strong offer from another school into getting $5k more per year back in 2017. I'm not sure if they still do this but it's worth asking Jessica Pan. You might be able to get more for all I know.
2) I have actually been able to get an assistantship for 3/4 semesters, and this is pretty common so you can mostly count on an extra $4k (really $3600 since it is taxed as income).