The “free card strategy” is actually just a way to get a look at a discounted card. This is a tactic best used when you’re holding a drawing hand. This tactic is not advised in many situations and the main purpose for its inclusion here is to teach you to recognize when it’s being attempted by your opponents and how to counter it.
To attempt getting the free card a player needs to be in good position in relation to the button or last to act on the flop. It is best used when there is a bet from an early position and a few players calling between. The free card play can now be done by raising with the intention of just checking on the turn, since players often check to a raising player on the next betting round.
Notice that the free card strategy isn’t actually a tactic to get free cards but rather a discounted one. Bets in Texas Hold’em are usually smaller on the flop compared to the turn or the river.
The downfall to any attempt at a “free card” is that there is no guarantee that a player will not be raised again which actually increases the cost. Another problem is you do not want to go for a free card when it could potentially drive away players that have not called the first bet. Losing these players will lower your pot odds and implied odds for the draw.
This means countering a “free card” attempt is super easy. If you have a strong hand and you suspect a player is trying to get a free card, just go ahead and re-raise on the flop. Many players make the mistake of trying to slow play and check raise on the turn, failing when a player takes the free card. This is why a re-raise is the correct course of action.
If your hand is strong but you are not sure whether the player is going for a free card or has a bigger hand and you want to be cautious. Just call on the flop and then bet again on the turn, that way there will be no free card.