The point spread is essentially a handicap towards the underdog. The wager becomes "Will the favorite win by more than the point spread?" The point spread can be moved to any level to create an equal number of participants on each side of the wager. This allows a bookmaker to act as a market maker by accepting wagers on both sides of the spread. The bookmaker charges a commission, or vigorish, and acts as the counterparty for each participant. As long as the total amount wagered on each side is roughly equal, the bookmaker is unconcerned with the actual outcome; profits instead come from the commissions.
Money Line: More common in baseball and hockey, pro football moneylines are growing in popularity. There is no spread, so your team just needs to win the game, not win by a certain number of points. The negative value means a favorite (-190) and a positive one indicates an underdog (+170). Picture the number 100 sitting in between these two values. Example: if you want to pick a -190 favorite, you must risk $190 in order to win $100. To back a +170 underdog, you put up $100 and win $170 if the dog wins. In some cases, betting moneylines is actually better value and can provide a bigger profit for less risk.