I currently just have express delivery.
Ok, I added convert to MP3 for $5, so they get a compressed and uncompressed version. I see a lot of people do the opposite and charge more for a HQ file which doesn’t make sense.
On the intro gig I added 10 second outro similar to the intro using some of the same instruments etc for $10.
I also added stems but I’m not sure how many people really want that.