Stop using shrink wrap
I've ordered several times and have had the plastic wrap ruin some of my stickers. Plus it's super wasteful. I order from other similar businesses and no one else shrink wraps their stickers and magnets so I don't see why it's necessary.
Allow smaller quantities
Sometimes we need very small quantities. it's not about price but avoiding waste.
I would suggest a rewards program where you earn points based on the amount of orders you place. IE you earn $1 in sticker mule discounts for every $100 spent.
Please please PLEASE consider a reseller program. There are 1700 of us resellers in my company alone who are always looking for new suppliers. Your process is the easiest out there by far. I bet you $5 bucks once my other dealers run an order though you they'd be hooked!
The last three orders I received were shipped inside plastic envelopes (incl. bubble wrap). It would be nice to see a more eco-friendly shipping option. I would even pay something extra for such a service.
Ship an order to multiple locations
Example: you buy 10,000 stickers and you want 1,000 delivered to 10 different locations.