Finding prices better than they should be (positive EV)
How to spot a sportsbook price that pays more than the bet is worth, and what to do once you find one.
Work out what each bet is really worth
Start from the markets that price games most accurately: sportsbooks that welcome professional money (Pinnacle, Betfair Exchange) and real-money prediction markets (Kalshi, Polymarket). Every price has the sportsbook's cut built into it (the vig) — take that out and what is left is the best public estimate of the outcome's real chance, which is what the bet is really worth (its fair odds).
Find a book paying more than that
Compare that number to the books built for casual bettors — DraftKings, FanDuel, BetMGM, and the rest. Any book offering longer odds than the bet is worth is paying better than it should, and that gap is your advantage (a +EV bet).
Decide how much to risk (Kelly)
The standard method sizes each bet to your advantage: the bigger the gap, the more it says to risk. Most people stake a quarter or half of what it suggests, because the full amount assumes your numbers are perfect. Whatever it says, never put more than about 5% of your betting money on one play.
Check the price moved your way (closing line value)
Write down the final price of every bet — the price just before the game starts. If you keep taking +150 on bets that close at +130, the market moved to agree with you after the fact, which is a sign the advantage is real even during a stretch where the bets themselves lose.
Common questions
Which sport is easiest to start with?
Whichever sport's player-stat bets (props) get the least attention at the books you use — usually NBA and MLB. NFL prices are tighter, because far more money is bet into every NFL line.
How much money do I need?
Enough that a single bet is a small slice of it — a common rule is at least 100 times your average stake. That cushion is what lets you sit through a normal losing stretch without going broke or panicking.
What tools do I actually need?
A price scanner (Parlae does this part), accounts at several sportsbooks, and a written record of every bet with the price it closed at.