Free bets can look straightforward until you check what happens to the stake....

https://super-wiki.win/index.php/How_can_I_spot_a_free_bet_offer_that_looks_good_but_isn%E2%80%99t%3F

Free bets can look straightforward until you check what happens to the stake. This guide for Irish customers explains the key terms to compare, including when the stake is not returned and how that changes your potential winnings