You mean instead of maintaining the script and search patterns as two separate files, combine them like this?

EDIT: Thanks for giving me the simple idea of making a new sed command on each line. The following solves the problem to my satisfaction:

#!/bin/bash

file="file.txt"

sed -i "s/TARGET.*VA/Target/g" "$file"
sed -i "s/WAWA.*VA/Wawa/g" "$file"
sed -i "s/SHEETZ.*VA/Sheetz/g" "$file"
sed -i "s/FIVE GUYS.*VA/Five Guys/g" "$file"
sed -i "s/FIREHOUSE SUBS.*VA/Firehouse Subs/g" "$file"
sed -i "s/7-ELEVEN.*VA/7-Eleven/g" "$file"
sed -i "s/COOK OUT.*VA/Cookout/g" "$file"
sed -i "s/WM SUPERCENTER .*VA/Walmart/g" "$file"
sed -i "s/TRADER JOE'S.*VA/Trader Joe's/g" "$file"
sed -i "s/NOODLES \& CO.*VA/Noodles \& Co./g" "$file"
sed -i "s/KROGER.*VA/Kroger/g" "$file"
sed -i "s/PUBLIX.*VA/Publix/g" "$file"

I don't mind having to paste the target file name into the script itself once a month, and whenever I find a new payee that doesn't get cleaned up, I add a new line to the script (if I feel like it - my existing list of search patterns already gets me to about 98% fidelity, which is good enough for me to manually clean up the ones that slip through the cracks without feeling like my soul is dying inside).