It is up to a social security disability attorney to analyze the case from all aspects and estimate the probability of success. An attorney has a right to decide whether they will work on your case or not after studying the files and documents carefully. They also have a right to set the price. Those could be either one-time fixed payment or hourly wages. Be ready that if your case does not meet most of the social security disability requirements, the attorney will most probably refuse to work on it and defend your rights in the court.