I contacted OK Comics and Travelling Man, two local comic shops to discuss their approach to stocking small press/self-published work. Below are the responses:
Travelling Man
"Most of the time it is Sale or Return but sometimes Wholesale, depending on how many we order to be honest, it really varies. We mostly wait for people to get in touch with us but again, sometimes we seek out and contact creators. Quantity wise, usually 2 or 4 copies per shop, but it really can vary! I've attached our guidelines too!"
Mama, who runs the small press for Travelling Man, also added their guidelines for me which detailed the ins and outs of getting paid and it was really useful.
OK Comics
"We used to purchase small press on sale or return but this was hard to manage, buying at a discounted rate (usually between 40/50%, we usually discuss this with the creator and find a price that works for us both) and letting them tick over works better for us. We also find that this gets us more excited to stock and sell the comic!
We tend to order a small amount to start with and gage customer response before ordering more,
Hope this helps!
All the best,
Danielle"