I work at a grocery store and I have a few lines that I have in my head that i cycle through that I know I won’t stutter on. Words that I know I will stutter on, I give myself a little more time before I say them as you can just bag a little slower or just slow down a bit. You dictate the pace of the transaction so if you need a little more time before you say something, that’s okay! Just take a couple breaths first and nobody will notice. I also hide blockages in the middle of my sentences and it helps it flow a little easier. Hope this helps :)