It's free for a limited time, not sure how long exactly. You can get it from here:
https://www.origin.com/irl/en-us/store/free-games/on-the-house
This game is one of the classics, a game I spent hundreds of hours on as a kid. I just finished downloading it so I haven't really checked if there's multiplayer, I really hope there is though. I also hope the game turns out actually good and playable and it's not just nostalgia that's making it seem so amazing haha!
Origin gives out some free games occasionally, I got Red Alert 2 a while ago from them. Enjoy!