Let It Ride - How to Play - Optional Side Bet

Some casinos offer an optional $1 side bet. This side bet offers an additional payout if the player's first three cards contains a winning hand. The house edge on this bet is generally over 13%, making it one of the worst bets for a player in a casino. A more common $1 side bet is against a fixed payout scheduling typically starting with two pair (typically a $4 payout, but really only 3:1 since the original dollar is collected before the hand is dealt) or three of a kind (typically a $8 payout).

From Wikipedia's

Let It Ride

Let It Ride
Basic Rules
How to Play
Strategy and House Edge