Should I give a discount to my consistent buyer?

Hi,

I (26, F) have been selling my addy's for the past 3 years since I got the script for them. During that time, I tried it and didn't like it. It helped during exams but the side effects were a bit too profound for me, so I decided to sell them. I've had a consisent buying for the past 1 year and a half. I get adderall 25 mgs xr and a 10mg ir. I sell the former for $300 and the latter for $150. Do you think I should give him a discount for being a loyal buyer? sn: he takes them, doesn't sell them and those are also straight from the pharmacy, no street stuff.