What do you mean sell them again with profit?
if you roughly know the marketprices, you will notice somethimes players are sold a little cheaper than average.
You can try to buy him for this cheaper price, and then relist him for a price a little higher then the average marketprice, but still within the regular prices.
example, say a type of player is regularly sold for prices between 100k and 150k.
Then if you see a player being sold and you can buy him for say 105k, you could relist him for 140k or 150k and hope to sell him.
Note that this is possible only for a limited amount of profit because you are not alowed to sell above regular marketprices. And if someone bids higher than what you know to be a normal price, you need to report this and the GMs will correct the amount you got for the player to a regular amount. If you do not do this, you risk an extra fine, or even a ban in severe cases or repeated cases.
Also when you sell to many players in a short time, the taxes on the sales will be so high that selling a player for 150k which you bought for 100k will actually not give you any profit at all.
So to do this effectively you need to spend a lot of time on the TL to get a good feel of the prices, and you are limited in your actions (which are brought into place to prevent users from playing the game through cheer day trading and not by playing good management).
And as you might figure out, will not be easy at all.
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