It's a thing to sell high, it's another to make fun of new player. People shouldn't even be able to put wood, water, seed and so on highter than what the troll/system sell.
Also maybe adding some limit to new player ? i mean seeing a beer 100k on the market (random good at high price so don't bother looking it may or may not have such beer on the market but it's not my first time seeing such price for such item), i can't help but tell myself it's a economic suicide (dat fee). So either adding a limit on item to avoid new player to do such thing or giving new player something like a low-grade prenium than only make them avoid market fee for the first few week/month of their playing.