On the official David Drake page, his family members have
a tribute plus a link to give to a charity (a scholarship fund) that David Drake supported.
Baen is offering a David Drake eBook sale
as a tribute.
You can get one dollar off individual eBooks -- or get the whole bundle for $87.87. The bundle can be viewed at the
David Drake Collection page.
I know this isn't a huge discount -- but keep it in mind if you're looking to support his family, buy eBooks you missed, etc.