Big news today. Although the DnD Classics site is down (EDIT: at the time of this post) the store pages at DriveThru and RPGNow are still running. Wizards of the Coast have released PDFs of a selection of older products right up until present day. It’s a bit of a random selection but today I picked up Moldvay Basic, B5 and T1-4 (see blog for details)
WotC store on DriveThruRPG
Adv&Shpg blog post