A lot of it depends on your local resources. I stress this because it's not going to be very fun if you have to order all your paints, glue, materials, and models from companies online and stuff like that.
If you guys want to start out small I suggest looking into Warmachine. For an example of their products...
KhadorGranted, I'm biased towards Khador.
In any case, lots of the stuff you see there is going to come as unpainted metal with the plastic bases. You need to touch up a bit of it sometimes from casting bits or whatnot ( bends in the case of spears sometimes ) and then glue together a few pieces. They're all simple and have the necessary instructions. Each of the factions play differently, and they all have their own personal styles in how they look and act.
Then you paint, and what you do with that depends on your level of skill and commitment.
Warmachines can be kinda expensive though, depending on your local markup. It's going to be like 50-60$ for a battlebox ( if they have one ) which will include your basic warcaster and 2-4 warjacks.
On the bright side, PP is switching over to plastic. Soon when you get a Juggernaut in the box, it's going to be made of plastic, but it's going to come with all the necessary pieces to build one of 3-4 different types of warjack, as you choose.