The 1/2 price is overkill. On the other side the pure marketing effect for a company like Spreadshirt (Spreadshirt is an internet company offering an online platform for private individuals and commercial organizations to design, buy and sell creative and personalized apparel) could catch on.
Creating awareness for a service or product, the pure advertisement effect should be the only and sufficient motivation to work together with a company.
Spreadshirt really should offer christmas socks with some text entry field on front.
edit: oh, how about mollesting webpages (blogs) for putting up a "Donate some Monero" sticker on their frontpage? a simple addition in their webpage's DNS entry allows recieving tips from their readers, something argueably PayPal or similar can do, too. but remember Bitcoin was for some timespan usefull for recieving tips. same old road to go!
That ended when the greed, the hunger and the Gox famine kicked in.