US Mint Sets - How were they sold from US Mint?

[ScrapMetal]

I have a box of US Mint Sets ( the ones that came in cellophane holders)all still in the shipping envelopes. Some have 2 sets of coins (P & D) and other have only 1 set of coins inside each envelope. I am curious how the Mint originally sold these sets. Looking at price sheets ( http://numismedia.com/fmv/pricesms/sets/prices.shtml )seems confusing to me as they do not list the single sets or they list P-D-S. Does the P-D-S mean that all 3 mint marks should be in the set, or does this mean that for any one of those mint marks that is the value?
And then on this website ( http://coins.about.com/library/US-coin- ... Values.htm ) they just list the year without any Mint mark (ie P D or S).

For example, I have 6 envelopes with 1961 (P & D) and then I have 18 envelopes with just the P mint mark.
I don't see any with the S mint mark. I am pretty sure this is the way they came from Mint , and no items were removed after purchase.

I am curious how the US MInt had their order form and how a person decided what to get for each year.

The US Mint sets that I have start from 1960 and continue to 1993.

My goal is just to get some reasonable list prices ( I know they are pretty much worthless).

[Verbane]

If P-D-S is listed, then all mint marks should be in the set. Example - 1973 UNC mint set is P-D-S, but the only S mint in the set is the penny, and is included in one of the two cello packs.

Concerning your 1961 sets - I think what you are seeing is UNC(Uncirculated) versus Proof sets. The UNC sets are P-D, the cello packs should include a round plastic P or D token. The "P only" sets are likely Proof sets with an Octagonal Foil/Paper Philadelphia token.

All UNC sets are P-D or P-D-S. Proof sets were made in Philadelphia up to 1964. SMS(special mint sets) were made in San Francisco 1965-1967 with no mint mark. Proofs are made in San Francisco, and mint marked "S" starting 1968.

The numismedia site is the better resource covering UNC and Proof sets, and prices are a good representation of market value. The about.com site is UNC sets only which is why they don't list P-D or P-D-S