Unfortunately the last bulk I bought was from Amazon a year ago but I just checked and Otto has them too. Although don’t expect them to be “original” Bundeswehr socks, I have no idea if they have ever been purchased by the German army, and searching for “German army socks” gives you tons of different results. Anyway I found these are very durable, comfortable and dirt cheap, so can recommend them. :)

https://www.otto.de/p/fussfreunde-sportsocken-10-paar-armysocken-bundeswehrsocken-outdoorsocken-mit-vollfrotteefuss-S0P890KU/#variationId=S0P890KUFJY1