I understand in reality coins are worth what people are willing to pay for them, nothing less, and nothing more. Also, I know the red and blue books only give you an idea what a coin is worth (though one of our coin stores here in Reno actually looks things up in the red book when pricing coins). However, I notice the red and blue book values don't change a whole lot from year to year, it seems to me, suggesting coin price fluctuations are somewhat temporary.
Don't be naive. Many coins change year over year. Some go up, some down. the main thing about the price guides like BlueBook is that they grant you the assumption that someone actually wants to pay you wholesale cost for your common date average coin. The fact is that most people won't. The coin is common and they can find them for little if no premium whatsoever. The key dates will generate more interest and therefore sell more closely to market prices more often.
Many Variables In Selling Sets I often purchase complete sets of the various coins as an investment through various venues, or purchase a virtually complete set, and locate the few missing coins. Similar to acquiring virtually any assembly, the sum of the parts is usually greater than a completed unit. This is generally true whether you're building a street rod or a home. The variable is usually sentimental value added by the seller. I purchase complete good/better sets at a reasonable value on eBay and other venues, often close to values stated in the C.D.N.. Partial sets are offered frequently, where a few coins are needed for completion. The set values are usually determined by average coin condition, the absolute condition of the "keys", and the clientele/venue selected for sale. An advanced eBay search will provide a reasonable synopsis of market interest for a type/condition coin set, thus: http://www.ebay.com/itm/1916-1945-COMPLETE-MERCURY-DIME-SET-W-1921-1921-D-1916-D-/370513573644?pt=Coins_US_Individual&hash=item564454770c I'd never expect to purchase a set at the buy price offered by B&M "dealers", as their infrastructure costs are relatively appreciable. "Dealers" are generally looking for a rapid "return on investment", often viewing the purchased product as a commodity. A collector/investor is generally more likely to enjoy a "set" accumulation, and consider it to be similar to other acquisitions which may not appreciate, often depreciating. If one is to expect the values determined in available documents, they generally must be willing to extend the efforts, accept the risks, and objectively acknowledge that their offering may have limited marketability resulting in undesirable "return on investment". An astute collector usually realizes that "return on investment" may be negative, as collectors generally purchase to suit their needs rather than the interests of potential buyers. I believe that most collectors will determine that the collection process is for mental appreciation, rather than financial. Just my humble opinion. :thumb: