Which chargers to buy for a charging station? To make a charging station effective, it needs to be able to charge all recent Apple laptops. As you know, Apple chargers are not cheap. So, we'd like to buy as few chargers as possible. 

Given this article, what would be the most cost effective way to set this up?

I've read online about how higher wattage chargers can be used for lower wattage computers. If we were to buy one Magsafe 1 85 Watt charger and a Magsafe to Magsafe 2 converter, would we be able to charge all apple laptops besides the new Retina Macbook Pro?
The answer is YES.

You can use the higher power Charger on lower power laptops. The battery will only take as much as it can handle. 

It is a pull not push process.

Extra info: If you were to use lower power charger on high power laptop, you could end up newer charging the battery fully, or it could take extended time to charge.