I bought the Menace of the Underdark Collectors Edition pre-order back in the day, so all of my characters have a Lesser Tome of Learning. During DDO Store sales when the Greater Tome of Learning is run at 50% off, the Lesser to Greater Tome of Learning is never included. The Lesser to Greater is the only Tome of Learning I can make use of, so I keep hoping that it'll eventually be included when the Greater is run on sale.

Of course, if the Lesser to Greater Tome of Learning was run on sale, it would tempt me to buy another character slot or two in order to have more characters make use of the sale. Then I'd be tempted to buy tomes and hireling folders for those new characters. Then I'd end up needing to buy more DDO Points.