While not exactly pricey to start with, they are even cheaper for the next week.
FR Collection One with the Eye of Beholder Games for $1.99
FR Collection Two with the FR Gold Box games for $1.99: Pools of Radiance, Curse of the Azure Bonds, Secret of the Silver Blades, Pools of Darkness, Unlimited Adventures (FRUA, the one that let you make your own games), and the two Savage Frontier games which was like the start of a second series but I guess never got anywhere since by that time people have moved on from them (I know I did)
It includes the manual and hint books so even if you don't plan on playing them, they are still kinda worthwhile to read.
There's a 3rd collection of FR games (only Menzowhatzerit and Dungeon Hack)
Icewind Dale Enhanced Edtion, while for 2e is an okay hack and slash game and is $3.99
Also 2e, Baldur's Gate 1 and 2 are also $4.99 each
The Krynn/Dragonlance games aren't on sale.