Every time you look at a spread or total, you'll see -110 next to it. Here's the plain-English answer.
-110 means you bet $110 to win $100. If you win, you get back $210 total ($110 stake + $100 profit).
That extra $10 is the sportsbook's cut — called the vig or juice. They keep it no matter who wins. It's how they make money regardless of the outcome.
Minus = you pay extra (betting a favorite). Plus = you get paid extra (betting an underdog). -200 means bet $200 to win $100. +150 means bet $100 to win $150.
Divide 100 by the minus number. At -110: 100/110 = $0.91 profit per dollar. At -200: 100/200 = $0.50 per dollar.
-110 is the standard price on spread and total bets. You bet $110 to win $100. The extra $10 is the sportsbook's commission. Always factor the juice into your math.