Tena, fees are generated using the following logic:  how many years does the client want searched, how far do I have to travel to the courthouse and what other overhead do I have (i.e. E&O Insurance).  Therefore, the only GOOD answers to your question will need to come from your area.  Here in SC, the counties are not nearly as far apart as in Texas. What usually works best is to have one or two BASE RATE counties--obviously, the ones closest to you and then have TIERS adding $10, $20, etc to the price the farther out you go.

My immediate concern is whether the client is willing to train you.  Abstracting CANNOT be learned from a book, online class or just by walking into the courthouse.  While I am a big supporter of small businesses, if your client isn't providing training, I would think REALLY HARD about whether or not to pursue this.  Basic abstracting can be learned fairly quickly (i.e. what elements are searched in every search), but PROFICIENCY is something you get only by experience--and that experience is BEST obtained while someone else is back checking your work.