Thanks for your answers, I'll try with auctions even if it takes time to understand how it works to not have bad surprises. My first Valkyrie offered during the tutorial got wrecked by creatures while exploring.. well too far, too fast I guess. The pity is that it cannot be repaired neither sold. It's a good lesson hehe.
Is it the same with other vehicles or can I repair a bought one in case of crash, for example let's say a helicopter or a VTO? (my dream for mining!)