The question is do you really need pickling salt for pickling? While pickling salt is ideal, it's not the only salt that can be used. Kosher salt is a great alternative, as long as it's pure salt without any additives. Read the label carefully. (Diamond Crystal is a good brand; avoid Morton, which does contain anti-caking agents.) Pure sea salt can also be used in pickling.
Although table salt is perfectly safe to use in pickling, it is not recommended because the quality of pickles may suffer due to its additives.
Substitutes for Pickling Salt
When making substitutions for pickling salt, keep in mind that weight per volume can differ. Salts coarser than pickling salt may also take longer to dissolve. The University of Wisconsin - Cooperative Extension advises that
1 1/2 cups of flaked kosher salt equals about 1 cup of canning and pickling salt, or about 50% more kosher salt. For fermented pickles, they recommend measuring by weight: 7 3/4 ounces (220 grams) of flaked salt is equivalent to 1 cup of canning and pickling salt.
University of Wisconsin Cooperative Extension .... Great Hand out!