Best build/class for going with a group?

I am a new player and will be playing most of the game with two friends. They are not so sure what class they are going to play, so if possible, their choices don't need to be taken into consideration. I am just looking for general suggestions on what an effective class/build is for playing with other players is, as well as not being too horribly expensive (if at all possible).

There are a ton of interesting builds from all of the classes that I like, but I am having a hard time figuring out if there are good builds for party play... or if that isn't even a thing, really.

Thank you, in advance. :)

You can try a summoner aurabot using Generosity on some damage auras like Hatred or Haste. Generosity enables the auras to affect everybody (including minions) except you, and it increases the effectiveness of said auras.

If you want more utility, try a skill that has an additional survivability effect. Take Ice Shot for example. It's an amazing hard-hitting bow skill that has the added effect of chilling/freezing enemies and leaving chilled ground. You can increase the duration of this chilled ground by using Increased Duration gem, but it's usually more effective to just have a higher attack speed.

Good luck, hope this helps!

If you want to do a more support oriented build you can never go wrong with using the Grace and Haste auras since nearly every existing build will profit from them.

You could, for example play an Iceshot Ranger with a skilltree similar to this one. Use the Grace, Haste and Purity auras to boost both your as well as your teams survivability and damage output. A slightly more solo play/offense oriented version could look like this and could still use a 3rd aura but only with the rather expensive but very powerful Alpha's Howl unique helmet. Or you could settle for just two auras and change the build for a more power oriented version which would still be very useful for teamplay but deals significantly more damage.

These are of course only examples since there are a ton of builds for different classes and types of gamelay out there that are well suited for both team and solo play but i chose this one mostly for three reasons:
1. it is relatively easy to play while still being relatively powerful
2. you can see how you can modify your build by taking different 'branches' in the skilltree wile keeping the same core build.
3. you can do nearly the same build starting with a Shadow instead. You will only trade some survivability for more damage because of the different starting nodes.

Culler, summoner.