I'm in the process of purchasing a certificate for my web app, and I'm getting a little confused by all the different certificates out there. I know that an EV certificate gives me the "green address bar" with my company name in the browser. An example of this can be seen at namecheap.com (you can see "Namecheap, Inc" in green). And if I go to a ssl reseller (such as ssls.com), they promote this as "Very High Assurance" (the EV certificate gets you the green bar).

But they have other certs for sale that use domain validation and give you a low to high assurance. What do these equate to in a browser? If I look at the cert for stackexchange.com, I don't see a company name like namecheap has, but I see a green phrase that says "Secure" instead. Does this equate to the non-EV ssl? If so, which one?

My ultimate question is this: what is the least expensive kind of cert that will get me a green bar in a browser, whether it shows my company name, or just the word "Secure"?