Well, I don't know of any really good KC BBQ supplies site that has all of our better stuff available online.
Generally, there's maybe three types of rubs.
Everybody makes a "rib rub", lots of folks make a "brisket rub", some folks make an "all purpose rub" and a few even make a "poultry rub".
Of course, some of these come in two versions, like a "regular" all purpose rub and a "hot-n-spicy" all purpose rub.
BBQ is just a continual journey of experimentation and enjoyment.
So, tell me what you plan to do and trust my judgement.

I'll send you like 2-4 rubs. Figure $3 each and shipping. You'll be real close and I'll enclose the actual receipts.
I'd start you out with a little Jack's Stack, some Gates, Bilardo Brother's or maybe some Hog's Breath. It's all good... you just have to find the one YOU think is best. And remember, variety is the spice of life.
As for the ECB, the El Cheapo Brinkmann, I used one for years. It can make EXCELLENT BBQ if you pay attention. This guy has the most extensive modification page/instructions I've found and it's good advice. Especially the Polder thermometer.
http://www.randyq.addr.com/ecb/ecb.htmlBe sure and go to his home page there and look at the "basics". Great info on getting started. It's a real good site overall.
Remember...... it's a journey and it's fun. There really isn't any "bad" BBQ unless you screw up in an incredible fashion.
Enjoy!