Apple iTunes now supports a new feature called 'Complete My Album'. The concept behind this feature is to allow those who have purchased one or more songs from an album to buy the rest of the album at a reduced price.
Prior to this feature, if you purchased a song or songs for $.99 then decided you liked the artist wanted by the entire album you had one of two choices. First, you could buy the rest of the songs on the album individually and lose out on the album discount. Second, you could buy the album which meant your were buying songs you already own.
Now with "Complete My Album", Apple will give you a credit for every song previously purchased. The credit is then automatically applied towards the purchase of the entire album. So, if you bought two singles songs at $.99 a piece , you would be credited $1.98 towards a $9.99 bringing the album price to $8.01.
There is one small catch however - the price reduction is only valid 180 days after the initial purchase. For songs purchased prior to the availability of this feature, Apple is offering a retroactive offer for a limited time. For these songs you only have 90 days to complete your albums.
There is a new link in the "Quick Links" section of the iTunes store that will bring you to a page that allow you to complete you albums.