I'm just now getting out of a situation like this that I've been in for 7 years. It's a position that I got after I dropped out of a CS program after the first year, and my inexperience and lack of education made me feel like I didn't deserve all that much. But I did my job well, orders of magnitude better than some of my coworkers.

I clued up about 2 years ago, and have been asking for more and more money on a regular basis. The breaking point was when I asked for a certain amount and they literally laughed at me. I immediately started making plans to leave. Next monday I start a new job where I will finally be making more than my age in dollars per hour.