My suggestion would be to go to the for sale forum here and look for a tc3 or xxx-s. These are older version of the cars, where the owners are either getting out or upgrading to newer versions. Every hobbystore that I've been to carries parts for those 2, after all they are pretty popular (or widely-sold) cars.
The advantage of buying used is that you can get lot of stuff extra, i.e. car comes with radio, speed control, motors, extra tires, bodies, parts, and maybe some option/hop-up parts. If you lucky you might even find someone selling batteries and charger too.
I would go with the idea of buying the same for both of you. Not only you need less parts, but then you can work with each other for the adjustments.
If you're a complete noob, then I would say have fun with this. When you get better, then you can start thinking of moving up to a later vresion. The first year I would say you be busy focus on driving and not breaking, and getting started getting familar with adjustments.
If you want to spend a little more money, the Team TC4 and JXRS are also available too on the resale market, but since they are more recent versions, people want a little more $$. But shop around you be surprised how much money you can save.