I pay through the nose for rosemary. Either way -- if I buy a potted plant that's of usable size or for little cuttings at the market. It doesn't over-winter here, and I think my house is too dry inside, so I wind up with a table full of needles like a Charlie Brown Christmas tree surrounding the pot.
Otherwise, I pretty much grow herbs I like to use, parsley, (+ 1 for tabbouleh) , sage, thyme, lemon thyme, tarragon, mint In Pots, (so it doesn't spread), oregano, marjoram, lots of basil. I plant a 2nd go-around with cilantro in about September when it's a little cooler. I can't figure how Mexico and other hot climates are able to keep growing cilantro. Maybe with continuous plantings.
Nasturtium leaves or flowers are fun to use as an herb, and can put a little peppery zip in salads etc, I forgot to plant some as I just remembered this now. I think I have some saved seeds and they should still grow this summer.