If you are serious, you need to make it easy as fuck for them to make a purchase. Never underestimate how legitimately stupid niggers are.
Don't worry about a website shopping cart, niggers don't think that far ahead. Apple Pay/Google Pay buttons on the page (displayed per their browser signature, just need to differentiate between safari and chrome, niggers aren't smart enough to use another browser). Don't do anything to confuse them. If you can get a 3 year old to navigate the site and successfully purchase something, you are in business.
Advertise on the charlamange niggers podcast and other niggerish venues. If you can get a dealer to use your custom printed baggies for crack or weed, that would be a good avenue as well. Free bags, but they have your logo and website address on them. I wouldn't be surprised if they started displaying the baggies like a trophy.
EDIT: If you can figure out how to accept EBT for "shutting the hallway bird up", you'll be a millionaire in your first year. You'll have to venture into the nest, so if you aren't a fan of the smell of menthol cigarettes and fried food, this might not be for you. That stink will not leave your clothes easily.