Making your own like Femmecreole said is a good option. I like to mix up a bit of extra-virgin olive oil, vinegar, and garlic salt/pepper for a simple dressing. Some people like to use salsa as a salad dressing.
The two dressing staples I have are Hidden Valley Ranch, and Kraft Seven Seas Green Goddess dressing (2 g sugar and only $2 at Walmart right now.) Both are on-plan if you use 2 tablespoons.
First Goal: 25-40lbs by December 25th
Second goal: To be decided when the first goal is obtained