Smartwool socks are merino wool, but you do pay a bit more for the "brand name". For me, it is worth it because I have yet to be able to wear a pair out. I wear them daily because of a foot problem which requires the extra cushion even in "dress" wear. So the black or charcoal Smartwool socks don't stand out too much against my dress slacks.
That being said, if you are o.k. with a sock which is clearly for outdoor (e.g. hiking boots, etc) wear, look at the merino wool socks at Bass Pro shops throughout the U.S. and online. Except for the colors, I can't tell a difference from the Smartwool brand. And Bass Pro has a pair with lifetime guarantee too. I've been very pleased with them, also.