Call and put options are quite common in the share market, but rarer in real estate.
In the share market, I can buy a call option for a share which I think will go up. Say, NAB is $31.50 today, and I think it will go up to $32.50. I could pay, say, 20c for the right, but not the obligation, to buy those shares at the end of next month for $32.00. I pay the 20c to the person who owns the shares.
If the share rises to $32.50 by the end of that month, the person who owns the shares must (if I ask) sell me the shares to me for $32.00. I can immediately sell those same shares for $32.50- so I make a profit of 30c (sell price less buy price less option price).
If the share does not rise above $32, the person who owns the shares keeps the 20c, and I lose my money.
A put works in the opposite way. If I think the market will go down, I can buy a put- and if the share has gone down to less than the "strike price", I make a profit. If it hasn't, I lose my premium.