I play on Agride and that I get rich from selling them and farming ressources. The top ones are alchemy plants (ortie, sauge, trèfle, etc) while the cheepest ones are cereals who never go beyond 12 Kamas Dofus Retro unit. Played on Merkator a little and it appears that the pattern remains the same there also, where wood, metal and especially alchemy plants pay large while cereals barely 500k. The best money-making method I’ve found yet is selling batches of 10 orange larva skin, however I believe that is only for Halouine so you get to it fast before the event ends.
If you want to sell your items at the best cost, make sure it ends with 20, 10 or 00. People seem to prefer round amounts, and if you check it yourself you’ll see 2025k has an additional 1 kama tax compared to 2020k. Same thing for every single amount. Your cost needs to be the exact same or a bit lower (~200) than the typical cost.
Not only are you able to earn lots of money by selling ressources, it is going to also level up your amassing professions so then you get to buy Dofus Kamas produce breads and stuff for inbetween fights. Obviously you will need lots of pods to pull off this so I recommend doing this with a strenght personality then transfer the cash to your other figures using the lender. I do so with a str/int Eca with a Blop griotte (lvl 50) along with a Gadjète ring (lvl 49).Sorry if I get some terms incorrect, I play with the french version of the Dofus game.