I believe SME's and large enterprises can get up to like 70% discount on shipping with UPS. Smaller guys (eg. mom and pop shops, eBay sellers, smaller franchises, etc.) get lower like 30% off but large enterprises and MNC's (ie. Newegg, Evike, Nike, etc.) get crazy discounts.
Actually it might be beneficial to sign up for an eBay UPS account to realize savings on your end if you need to ship things out and you may even get favourable treatment for inbound packages. http://pages.ebay.com/upssavings/index.html