Is it possible for example to sell a property you own to another player for 1$? I was playing with some friends and one of them had to pay me 1200$ and since he didnt have enough he sold all his houses reached 1200 gave me the money and then sold all his stuff for 1$ to another player.
Yes, you can sell your properties cheap.
No, you can't do this when you are resolving payment for the space you landed on.
The only time a sale cannot take place is if a player will be cheated. For example, Player A lands on Boardwalk with hotels and owes $2,000 to Player B. Player A cannot raise enough cash or make a trade with Player B, so he is effectively bankrupt and should turn over all assets. Player A would not be able to make a deal with Player C to sell some properties for less than their value (say the red properties for $1) since that would cheat Player B. He could sell them for more than their purchase value, however.