Hello Greta! There are several spawn shops and town shops that purchase items - I currently purchase sand, cobble, and dirt in my shop, station12.
Unfortunately, most food will need to be sold in game to the server @/sell hand.
Make sure to keep an eye on the forums as many players advertise when needing items.
Wishing you success!

 

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@Greta - @AdmiralD's advice is spot on, good luck.