Thinking about buying my first snake

[craigafrechette]

Most expos have the vendor list posted online. You can check the website and cross reference sources.

ExoTerra will be fine for the enclosure.

Thermostats you can buy online. I've been using JumpStart for years with no problems at all.
HerpStat is a fantastic brand, cream of the crop, but pricey.

For thermometer/hygrometer I use Accurite brand. They can be found at Walmart or on Amazon for around $10-12 each. I have two in each of my enclosures.
As for treating the water... If you drink it it's safe for your snake. If you need to treat your drinking water you'll want to treat the snakes water as well.

To keep your humidity up, choosing a coco coir substrate will help immensely. You can also cover the majority of the screen lid to keep humidity in. Adding a humid hide during sheds would be a good idea.

Lastly, I'm not sure if it's just a matter of wording, but I want to make sure you're only getting one snake. Your sentence saying "I want them to be happy in their new home" is throwing me off.
Kings definitely can't be cohabitated. Kings are actually known to be cabalistic, so you definitely only want one in each enclosure. Otherwise you'll likely wake up one morning to one King with a very full belly