Buying Sea Salt? You Might Be a Sucker.
teddziuba.com
teddziuba.com
The iodine issue is true, although you would have to go out of your way to get iodine deficiency living in any 1st world country.
And as you mentioned, getting enough iodine isn't that difficult, especially given the amount of salt in most of what we eat, and the ability to get enough with some yogurt, cheese, and eating fish regularly. Besides, if you think you aren't getting enough iodine, just start watching for a goiter! :)
You can buy 4 pounds of standard issue table salt for $5.37 on the internet. Alternatively, I've seen 4 ounces of sea salt for sale for $2.39. That's a markup of roughly 712%.
Sea salt is 5 pounds for $3, here: http://www.herbco.com/c-184-salt.aspx