Underneath "When did in play betting start?" sits a method that takes two bets. Matched betting turns a book's free bet offer into a small, mostly predictable sum. The bettor backs an outcome with the book and lays the same outcome on a betting exchange, so that whichever result comes in, one side covers the other. The profit comes from the offer itself, which is why the method depends entirely on the promotions books choose to run and on following each step with great care.
How matched betting works shows in two steps. First comes a qualifying bet: a back bet with the book and a lay bet at a close price on the exchange, which usually costs a small fraction of every unit staked. That unlocks the free bet. The free bet is then matched the same way, and because its stake is not returned when it wins, the lay is sized smaller, leaving most of the free bet's value as a return locked in.
Is matched betting legal? It uses ordinary bets and ordinary offers, so it is legal wherever betting is, and the offer terms are the only rules in play. Books do not welcome it, though, and many watch for it. An account that only ever takes offers and never bets otherwise is often restricted from future promotions, and that restriction is what ends most matched betting runs well before the offers run out on their own.
How to start matched betting is mostly admin. A new bettor needs an exchange account, a clear record of every offer and every bet, and a simple calculator that sizes the lay stake from the two prices and the exchange commission. Starting with one offer at a time, at low stakes, and checking the terms line by line before placing anything avoids the errors that cost more than the offer is ever worth.
Asked about this
What does the qualifying bet in matched betting cost?
A back bet with the book and a lay at a close price on the exchange usually lose a small fraction of each unit staked, which unlocks the free bet.
What happens if a back bet is voided but the lay stands?
The exchange side is no longer covered, so the lay can win or lose on its own and a planned small gain becomes a real loss.
Why is the lay on a free bet smaller?
A free bet does not return its stake when it wins, so a smaller lay balances the two sides and locks in most of its value.
Do books restrict matched betting accounts?
Many do. An account that only ever takes offers and never bets otherwise is often barred from future promotions, which ends most runs.
Why read the offer terms before placing anything?
One missed line in the terms can void the free bet or change how it pays, costing more than the whole offer is worth.