The basic principle of point spreads and totals is that you have roughly a 50% chance of winning, so technically a "fair" return on these types of wagers should be equal to the amount staked. However, they are usually priced up by bookmakers at odds of -110 (1.91 in decimal odds format, 10/11 in fractional odds format), which means for every $110 staked you stand to win $100. You don't have to stake as much as $110 of course, but the point is that a successful wager will only return 90% of the amount staked (plus the initial stake of course).
A lot of betting strategy is very complex, and it definitely helps to learn some of the more advanced concepts if you want to be truly successful. However, trying to get your head around complicated strategies is NOT the right approach as a beginner. There are several simple betting systems that are relatively easy to understand, and it makes much more sense to start with these. They're not guaranteed to bring immediate success, but they can be effective if used correctly.
82 games per year means a lot of opportunities to wager on your favorite teams and sees that opportunity and gives you what you want to bet on. Sometimes this means having spreads for big games a day or two in advance, especially if both teams are off the day before the big matchup. They take care of their NBA bettors... give them a shot.
A listed odd with a – sign in front of it, such as the -140 in our example above, shows us how much money you would need to wager in order to win $100. So using the -140, this would show us that you would need to bet $140 in order to win $100 in profits. You can easily substitute the $100 bet for a $10 bet by moving the decimal place over one spot, showing us that you would need to wager $14 in order to win $10 in profits.
The rule against gambling in baseball is known as "Rule 21," which is publicly posted on dugout walls and states: "Any player, umpire, or club or league official or employee, who shall bet any sum whatsoever on any baseball game in connection with which the bettor has a duty to perform shall be declared permanently ineligible." People permanently banned from Major League Baseball are also forever banned from entry into the Baseball Hall of Fame, although most such people have been reinstated a few years later by a later Commissioner of Baseball. For instance, Mickey Mantle and Willie Mays were both banned from baseball in 1983 after taking jobs as casino greeters (which would have expelled them from the Hall of Fame had it been allowed to stand); they were reinstated two years later. Only Rose has yet to be reinstated.
A favorite (e.g. Patriots -280) on the money line works just like our bet price example above.  In our new example, the Patriots are listed at -280, meaning you would need to risk $280 for a return of $100 on them.  It follows that a winning bet on the Pats pays $100 (plus your initial investment of $280 back).  This added risk is why betting the spread is usually more popular, especially on favorites.
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.