Echoes is not for sale except with the full album, as it's the length of about 5 normal length songs. you can get the full album, Meddle, for $11.99, a higher price than most albums.
You can only get Echoes if you buy the whole album on itunes. Checkout my screenshot.
I already have this on cd and have ripped it into itunes via 160kps AAC. If you want me to send you the file for that song I can. What is the best way to do it? It is a 27mb file