Example: If you are betting the Lakers -5 -110 (lay $110 to win $100), you can buy the Lakers a half point to -4.5 -120 (lay $120 to win $100). You can buy the Lakers a full point to -4 -130 (lay $130 to win $100).
Same theory is true for the underdog. If the Bulls are +4 -110, you buy the game to +4.5 -120 or +5 -130.
You can only buy a maximum of 3 points in Football and Basketball, both college and pro.
There is one special rule. When buying on or off the number 3 in the NFL, there is a premium cost of 20%, not 10%.
Example: to move the Chargers from -3 -110 to -2.5, the new line will be -2.5 -130 (lay $130 to win $100). The same is true for the underdog, to buy Bears from +3 -110 to +3.5 will be -130 (lay $130 to win $110).