Sportsbook promos are not free money. Here is the math.

You open a sportsbook app during a game and see a banner: bet five dollars, get one hundred and fifty in bonus bets if your team wins. It sounds like the app is handing out cash. It isn't. It's a marketing offer with a discount built into it, and the discount is bigger than most people assume.

This post walks through the actual arithmetic. Not the marketing copy, the numbers. The specific figures below are worked examples we constructed to illustrate how these offers function generically. They are not a quote from any real operator's current terms, which change constantly. Anything presented as a specific real-world offer detail should be confirmed against that operator's current terms before you rely on it.

What is a "bet and get" offer, really?

The basic structure: you place a real-money bet of some size, say five dollars. If it wins, you get your normal payout in cash. Separately, regardless of whether that first bet wins or loses, the sportsbook credits your account with a set amount in "bonus bets," commonly a much larger number than your original stake.

The bonus bets are not cash sitting in your account. They're tokens you can use to place additional bets. This distinction is where most of the hidden cost lives.

Why aren't bonus bets worth their face value?

Here's the mechanic that matters: when you place a bet using a $50 bonus bet and it wins, you typically keep the winnings but not the $50 stake itself. Compare that to a normal cash bet, where a win returns your stake plus your winnings.

Let's work through it. Say you get a $50 bonus bet on a wager with even odds (bet $50 to win $50, sometimes shown as +100). With a cash bet, a win nets you $50 profit and you also get your original $50 back, for $100 total returned. With a bonus bet, a win nets you the same $50 profit, but you don't get the $50 "stake" back, because it was never really yours. You walk away with $50, not $100.

That means a $50 bonus bet at even odds is worth roughly half its face value if it wins, and worth nothing at all if it loses. Averaged across many bets at roughly 50/50 odds, a $50 bonus bet's real expected value comes out closer to $25, not $50.

Working the full example: bet $5, get $150

Let's put real steps to the headline example. You bet $5 of your own money on a game. Win or lose, you receive $150 in bonus bets, typically split into smaller chunks like six bonus bets of $25 each, because sportsbooks often cap individual bonus bet sizes, and the actual split and caps vary by operator and promotion.

Step one: your $5 real bet. If it wins at typical odds, you might get back $9 to $10. If it loses, you're down $5. Either way, the $150 in bonus bets still arrives, since that part of the offer isn't conditioned on your bet winning in most versions of this promo, though some versions do require the qualifying bet to be placed and confirmed before the bonus is credited, so check the specific offer's terms.

Step two: using the bonus bets. Using the math above, each bonus bet at roughly even odds is worth about half its face value in expectation, because a win doesn't return the stake. Six bonus bets of $25 each, each worth roughly $12.50 in expected value at even odds, adds up to about $75 in expected value from the $150 in bonus bets.

Step three: totaling it up. Your $150 headline offer is worth roughly $75 once you account for the no-stake-returned mechanic. If the odds you're forced to use on the bonus bets are worse than even (which is common, since favorites or parlays are often suggested), the real figure drops further, potentially to $50 to $60.

The offer isn't fake. Seventy-five dollars in real expected value for a five dollar outlay is still a good deal on paper. It is not, however, one hundred and fifty dollars of free money, and the gap between the headline and the reality is exactly the size most people underestimate.

What about deposit match bonuses?

A deposit match offer credits you a percentage of your deposit, commonly framed as up to 100%, in bonus funds. Say you deposit $200 and get a $200 match. The catch is almost always a playthrough or rollover requirement: you might need to wager that $200 a set number of times, for example ten times over, before you can withdraw any of it as cash.

Ten times over on $200 means placing $2,000 worth of total bets before the bonus converts to withdrawable cash. At a typical sportsbook hold (the house edge built into the odds), rolling $2,000 through bets will itself cost you money along the way, often more than the $200 bonus is worth by the time you've met the requirement. Specific rollover multiples and hold percentages vary widely by operator and market, so always check the current terms before treating a number like this as fact.

"But I still made money on that promo"

Consider a composite scenario, not a real account of a specific person: you sign up for three different sportsbook apps in the same month, each offering a bet-and-get promo. You calculate that between the three, you came out about $150 ahead after using all the bonus bets. That's genuinely possible, and some people do make a habit of collecting these offers without ever gambling recreationally afterward.

The risk is what happens next. The promos are a one-time or occasional event. The habit of opening a sportsbook app, watching odds, and placing bets is not one-time. Several people who start out only chasing promo value describe drifting into regular betting once the free offers run out, because the app, the habit, and the excitement are all still there.

Why do sportsbooks offer this if it costs them money?

It doesn't cost them as much as the headline number suggests, for the reasons above. It also brings in a new customer who now has an account, saved payment details, and a habit of opening the app. The offer is a customer acquisition cost, the same category of spending as a TV ad, calculated to be profitable for the operator over time even after the promo payout.

How do you evaluate whether a promo is worth it?

A few questions help cut through the marketing:

• Do you keep the stake on a winning bonus bet, or only the profit? This alone can cut the value in half.
• What odds are you required to use the bonus bets on? Being pushed toward parlays or heavy favorites reduces real value further.
• Is there a rollover requirement on deposited or bonus cash, and how many times must it be wagered before withdrawal?
• Would you be opening this account and placing bets even without the promo? If not, the promo is creating a habit, not just adding value to one.

What if promos are pulling you into betting more than you want to?

If you notice you're chasing promotional offers across multiple apps, or using the arrival of a new bonus as a reason to deposit money you'd otherwise have left alone, that's worth paying attention to. Promos are designed to lower the psychological barrier to signing up and betting. That's their job. It doesn't mean you have to accept the invitation every time one shows up in your inbox or on a broadcast.

If sports betting is taking up more time, money, or attention than you want it to, the National Problem Gambling Helpline at 1-800-522-4700 can point you toward support that's specific to sports betting, not just gambling in general.