basics

The Basics of Baseball Betting
While football and basketball are the most popular sports to bet on, baseball could be the easiest for beginners once you understand how to read the money line. Money line gambling is the primary wagering option for baseball bettors, which involves betting on the straight-up game outcome with no consideration for a point spread. Oddsmakers use the money line so that more money must be risked on the favorite or expected winner and less money on the underdog to balance the action on both sides.
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For example, our favorite newbie bettor Emily is a huge fan of the Boston Red Sox, who are favored in a majority of their games as the defending World Series champions. The money line on the Red Sox against the last-place Tampa Bay Devil Rays might be -170, with sportsbooks making bettors wager significantly more money on the Sox than the Devils Rays because it is more unlikely that the Rays would win the game. In this particular case, the -170 means a bettor who likes the Sox would need to lay $170 down to win $100. Conversely, Tampa Bay would be +150 based on the common 20-cent line used in baseball (the difference between -170 and +150), meaning a $100 bet could earn $150.
Keep in mind that sportsbooks only make a commission (also known as juice or vigorish) when the favorite loses. So if Boston loses, the book pays off $150 to underdog bettors while collecting $170 from favorite bettors, for a $20 profit. If Boston wins as expected, favorite bettors collect $100 while dog bettors lose $100 – resulting in zero profit for the bookmaker. The bigger the favorite, the less likely the underdog will win (and the less likely the book will collect their commission). To compensate for making a profit less often, sportsbooks increase the spread between the favorite’s lay price and the underdog’s payoff, making their commission bigger when the longshot underdog does win.
Some quality sportsbooks even offer a 10-cent line on baseball (also called the "dime" line), which would net a $160 profit. The "dime" line is especially appealing due to the fact that it offers half the juice as a normal football or basketball bet, so the bettor is charged half as much for making a wager.
A critical factor to consider when betting on baseball is the importance of starting pitching. With football and basketball, team vs. team handicapping is key - but with baseball you have double the chance to find an edge since both team and pitching match-ups can offer a winning edge. Starting pitchers obviously play an important role in the outcome of the game, and oddsmakers make the money line with them in mind.
One example would be the Red Sox being listed as a bigger favorite with ace Curt Schilling on the mound than when they send Tim Wakefield out there. Since Schilling is obviously the better pitcher, oddsmakers take that into consideration and would make him a bigger favorite than Wakefield since Schilling gives the Sox a better chance to win.
Money Line in Over/Under Totals
Total bets in baseball are based upon the combined number of runs scored by both teams. For example, if the Over/Under total of a game is posted at 9, and the combined runs of both teams adds up to less than 9, the Under wins; if the combined runs add up to over 9, the Over wins; if exactly 9, the total bet pushes.
Since there is much less scoring in baseball than football or basketball (making each run more significant) bookmakers often need to adjust the money line of the total in an effort to more subtly even the action. Imagine a game in which the total of 9 is too high, but the total of 8.5 is too low. The standard money line on totals is -110 each way, but in this case the money line would likely be adjusted to 9 UNDER -120, meaning you can bet under (the slightly too high number of 9), but the trade off is you must risk $120 to win $100; if you're willing to bet over (the slightly too high number of 9), you can do so with the appealing money line of +100.
The standard money line on totals is -120/+100 and is often stated in shorthand as 9 OVER (or 10 UNDER, etc.), but the money line can be adjusted even further. Example: 10 UNDER -140 (the over would pay +120).