Michael, whats your contact info? If your looking to use Shopify POS, BizArmour is able to link our merchant account directly into the POS. You get a discounted pricing of 0.4% + $0.10 per item. It's quite a bit lower than the 2.5% + $0.30 standard.
Within the US, the card brand charge a higher interchange rate than they do for Europe. So these flat price programs sometimes fit smaller US based businesses but will be far to costly for a business outside of the USA.
Go to http://gobizarmour.com/contact.html and we'll get you taken care of.