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The effective date found for a price list, is is the date that the price list will be active from. Price lists that have a future date will be modifiable until the effective date. From the effective date the most current price list will be active, and won't be found for modification. Price lists can be used for updating a product price form a certain date forward. The price list drop down no longer includes expired price lists.
A merchant with merchandise that will be set a different price for part of the year, can create a price list to be effective the June 6, 2012, that list will be modifiable until it's effective date. From that date forward the new prices will be in effect and won't be able to modify that list. They can however, create a new list, or a Price Book if if they wish to be able to set the prices to be active and inactive.
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