Why do marketers limit special pricing to one per person or household?

I've noticed resellers sometimes offer great deals but with the restriction you can only buy a limited quantity per person or household. From a consumer perspective, it may at first glance seem frustrating or unintuitive: If I buy one, I get a discount, but if I buy lots, I don't.

Why wouldn't they want to sell more units? How effective is the strategy as a marketing tool?

One possible motivation I came up with is to generate buzz for the product or drive traffic to their store by advertising a price well below that of competitors. Essentially they're trading margin for exposure (or put another way, selling you a discount in return for your attention). You buying more units beyond that first one doesn't get them any incremental gains in exposure, hence the limit.

But are there other good reasons for a reseller to impose limits? e.g. Do manufacturers ever offer incentives based on how many customers are sold to, rather than how many units are sold?

Is there any special term for this strategy in marketing circles or the academic community? How does it compare to other methods of "buying exposure"? e.g. Giving away coupon codes, running weekly specials, or just using the extra money to buy more traditional advertising. Can anyone provide some real-world insight, or better yet has the effectiveness ever been measured in a quantifiable fashion?

http://www.sitepoint.com/scarcity-marketing/ might be helpful to review.

There are a variety of reasons to do this, some include:

• artificial scarcity
• hype surrounding being an early adopter
• loss leader approach: the first to buy pays little, the next pays full rate
• prevent excessive reselling via non-traditional and/or unapproved channels (eg eBay)
• attract a larger initial customer base, viewing additional purchases per household/address to be the same customer, and not a new person