-115 is a standard betting line you might see for a soccer wager. You could see these odds for any type of bet, including moneylines, spreads, props, and goal totals.
An example from the English Premier League would be if Manchester United was -115 vs. Tottenham, and you bet Manchester United. You would have to wager $115 to win $100 on a Man U victory. If the match ends in a draw, or if Spurs win, then you would lose your bet.
Here's another example of -115 soccer odds from a recent match between Newcastle United and Aston Villa:

Anywhere between -110 and -130 is considered close to even odds on a bet, so you will most commonly see odds floating around-115 when it comes to spreads and goal totals.
Website
Bonus
Promo / Sign Up