Finding Affordable Dental Insurance?

I am a 24 year old female and live near Dallas, Texas. I am married and my spouse is a full time college student and I am the only one currently working to financially provide for us. I haven't been to a dentist in 5 years. I have 1 cavity (that I am aware of), extremely sensitive teeth (it started within the last year), and my teeth have shifted a lot since I lost my retainer. I haven't had my own dental insurance since I was on my parents' plan, and I do not know where to begin. I need to have my teeth cleaned and put sealant on my teeth to prevent further damage to my enamel or cavities. I am alright with paying on an "as needed" basis or monthly basis. My husband and I only have about $700 a month (give or take) to work with. Anybody have any hints or tips? Thanks so much and God Bless you guys :)