Here are a few guidelines you can use for help with determining approximate manufacture dates your decks of cards.
* The white labels are tax-free stamps. These started to be issued during World War Two, when the US Congress canceled taxation of select products (including playing cards) being sold to members of the US Armed Forces. Since the US didn't enter the war until December of 1941, the decks are likely not older than 1942, and as taxes were repealed in late 1965, they'd be no younger than that year. It's possible, however, that the tax-free stamps were discontinued earlier than the repeal date of the tax - certain government-issued tax-free stamps ended around the time of the Korean War in the early 1950s, but the white labels are private-issue stamps made by the manufacturer, the US Playing Card Company (USPC).
* The "1 Pack" tax stamp came in two designs, one rectangular and one square. Both were in use from 1940 to 1965.
* When playing card taxes were repealed in 1965, private manufacturers replaced them with their own stamps out of tradition - their customers had come to expect seeing some kind of seal over the flap of their playing card tuck boxes. Moisture-activated stamps were in use by USPC from 1965 until some time in the early or middle 1980s - you can identify them by the perforations on the edges where the stamps were torn before being stuck to the box, much like old postage stamps. At that time, they were replaced by self-adhesive stickers using a nearly-identical design that has smooth-cut edges and rounded corners.
* Barcodes started appearing on USPC decks at roughly the same time as self-adhesive stickers started to be used for deck seals, in the middle of the 1980s - the exact date isn't known and could even vary from brand to brand.
* In 1992, Bee playing cards had their tuck boxes redesigned and were no longer monochrome (single-color, usually either red or blue). This was to celebrate the brand's 100th anniversary. The first year of manufacture, 1892, is the reason why there has always been a "92" on the Bee Ace of Spades. Modern Bee deck tuck boxes made since 1992 are usually printed with blue, red and gold ink. Be aware that COUNTERFEIT versions of Bee playing cards printed in China are often sold in the older, monochrome-box design!
* International and Canadian versions of Bee deck boxes have gold borders. International versions of Bicycle decks boxes have gold borders. Canadian versions of both decks have barcodes on the backs of the boxes instead of the bottoms. Canadian USPC decks made before 1991 were manufactured in Canada under the name "the International Playing Card Company," which has since become a sales division of USPC. So USPC-branded decks marked "made in Canada" would be pre-1991, while those marked "made in USA" are 1991 and newer.
* When USPC moved its manufacturing from Cincinnati, Ohio to Erlanger, Kentucky in 2009, three notable changes were made in their packaging:
- Bicycle decks had their boxes redesigned from what's now called the "classic" design to the "Standard" design. The classic design is still available in an updated form as Bicycle model #807 but it not anywhere near as common as the Standard box design that replaced it.
- In addition to barcodes, box bottoms started to be printed with small-print legal information regarding copyright and name of manufacturer. The copyright year given is usually the year of manufacture.
- Most common brands of USPC decks were seals with red or blue deck stickers just before the move - the color was changed to black at the time of the move and is still black today, though special-issue decks can have a variety of different seal colors and types on them or no seal at all. It's worth noting that even if the box states that a deck was made in Cincinnati, if the deck seal is black, it was probably made in Erlanger and packed into a box that was left over from Cincinnati, which also means that it was probably made in 2009 or 2010.
That should serve as a good primer for dating a deck that's still sealed.
As far as the condition of the cellophane, while it's important for some collectors that the cellophane be intact, it's also a simple fact of physics that cellophane continues to shrink and become brittle over time - it's almost a given that an older deck, still wrapped, will have breaks in the cellophane. This is actually a good thing - if it doesn't break, the cellophane is capable of twisting/warping the box and the cards inside as it continues to shrink. For vintage decks, usually an intact deck seal is adequate proof that it's still in new condition, even if it's no longer in as-issued condition - and for many collectors, there's little to no difference between the two, especially factoring in how few vintage and antique decks are found in new condition with the box intact.
Value is another beast altogether. Value, like beauty, will always be in the eye of the beholder. The rule of thumb I use most often is to look for similar or identical items that have recently sold on eBay, though this works best with items that are at least semi-actively being traded. I look only for successfully completed sales, especially auctions - never for active sales and never for items that weren't bid on or purchased. This never guarantees you'll fetch the same price, but knowing what someone else recently paid will help clue you in as to what you might get, if you were to sell today. It might also be considered acceptable as an appraisal value if you're attempting to insure your collection, though you'd have to ask your insurer to be certain.
When an item hasn't sold recently, though, you have to approximate a bit more, using items of similar make and vintage as your guide, with perhaps a tiny premium for the fact that the item, not having been on the market recently, might be a little bit more scarce. Conversely, though, it could be the case that the item isn't on the market because it isn't desirable enough to bother with - if you have any doubts, it's better to consult with people who trade actively and get their opinions on the specific item in question.