I wanted to setup a shopify store front and send out stupid meme related postcards or anything of that matter. In return send bitcoins at market price
postcard-30$ profit 28$
I would pay the 2.9%+.30cents
28$-2.9%-.30cents=$26.92profit
shopify would provide security for debit card transactions
and i can validate shipping so people couldn't try to gain bitcoins and reverse transactions
any comments or concerns you think i would encounter?
Getting $28 profit from $30 postcards is a pretty solid business model.

Your profit won`t be that high because you have to invest in advertising and drive some traffic to your shopify store.
Does Shopify accept bitcoin as a payment method?It would be great if they do.
I don`t understand something.
You want to sell bitcoins and mask this as postcards selling or you want to sell postcards and get paid with bitcoins?