If you hit up the For Sale section, you'll find a few members who sell ferts.
Green Leaf is also a popular seller.
Something that may help you make the decision about where to purchase would be to use the search function at the top of the forum. Check the most recent threads for details about where people are buying to see what's current.
+1 for nilocg. Like being able to buy just what I need. I don't use much NO3 but do use more GH booster & potassium. So like being able to customize to fit my needs. Plus I can get Osmocote tabs from him too.