How much is a Steem Dollar Worth ?

I want to start buying and selling my wholesale goods using Steem and trying to figure out what it's value is in relation to 1 USD December and January. I thought I had read somewhere that it is 1:1 but that doesn't seem to be the case. I found this link but if Steem drops to one penny then it would be tough to use for merchant transactions, maybe I'm just to new to the whole Steem thing, I guess I have to read the basics with more clarity.
If you were a wholesale merchant and you wanted to sell or buy using Steem you would probably want to make sure this is clearly understood same as me. Thanks to everyone in the Global Community for your patience with me and my question(s). Aloha, Rich