there there a hack out there that allows 2 users to play on one cd? i dont want to buy another set so i was wondering if me and my friend can both play on just his set.

No there isnt. At least not one to my knowledge

nope, cant be done. unless you guys are on different servers

Only if you play on two different realms, so you wouldn't be able to play with or talk to your friend.

No, thats not even possible for multiple people to be on 1 CD. But he can use D2Loader to use the No-CD Loader so he doesnt have to use the CD, then you can use it. If he deosnt feel comfortable giving you the CD then you can use the No CD Loader to.

http://www.blizzsector.net/hacks-dupes-guides/28928-d2loader-guide.html?highlight=loader

He would still need his own CD key though...

You can use the same cd key on different realms, on the same realm you get the message cd key in use by x.