They are an interesting contrast in value vs page count. AAs tend to be expensive and only about 16 pages, yet pack a huge amount of adventure into them (for instance, AA#41 has 112 areas). On the other hand, Spire of the Kobolds was $1 and 7 pages, yet somehow only manages 7 encounter areas.
Polyhedron 51, 52, and 53 - 51 has an adventure, 52 seems to be devoted to non TSR games like Paranoia, and 53 seems to have a 0 level adventure. 99 cents each
Creeping Cold - The players are trapped in a remote inn in this module for S&W for levels 3-5. $10, 36 pages.
From the Mouths of Babes - Odysseys & Overlords adventure about wolves gone mad. For 2nd-3rd level. $1.95 and 16 pages.
Ruins & Adventures 3: The Sanctuary - Tiny site based adventure in the ruins of a small village for B/X. $1.50, 12 pages.
SSolo1 The Endless Lair - From Starry Knight comes this solo adventure for 1e, for characters 3 to 5. 16 pages, $2.50.
The Crypt of Rokar - Small tomb crawl for B/X-ish systems, 1st or 2nd level. 10 pages and PWYW
RPPP Medieval Authentic (tm) Ipswich - Man, I miss chipwichs. $2.99, 26 pages.