Macbook Pro 2011 and 2012. still useable? Need a power supply for each one. What power supply?

Find the right power adapter and cable for your Mac notebook - Apple Support

13" or 15"? The former used a 65 Watt charger; the latter used an 85 Watt charger. Both can be purchased from Apple. But be sure to get one with the proper cable. Your models used a MagSafe or MagSafe 2 connecter depending upon the exact models that you have.