Fanduel have an excellent promotion to get you to try the Fanduel Same Game Parlay. Simply place a 3-legg SGP on any NFL Week 2 game, and if your bet loses, Fanduel will refund you in site credit, up to $10.
There are a few requirements, such as: the wager must have final total odds of +400 or greater, you need to opt-in and the minimum bet is $1. These are of course only pre-match odds.