The A&K 249 is a good testing the waters step into support guns. Pretty well 100% reliable, commonly available and good knowledge base about running them.
The more out there choices like a MG42 or Minigun are going to set you back 3-6K or so on a good day. The only G&P 249 I've seen for sale on here in the last five years had a cracked body so it was not desirable. If you want to spend a bit more you can get the slightly nicer Classic Army version that the A&K was copied from.
The only downside I've found is that you do run through more ammo than if you had a rifle. That may not be an issue for you.
The best way to buy is to first of all hit a few games up and see one in action so you can decide for sure. While you're doing that start saving up and watching the classifieds on here for a good deal. It's spring and for sale ads will be popping up soon.
Airsoft, where nothing is hurt but feelings.