If there is a dental school in your area you may be able to get at least the fillings that are in bad condition replaced for very little or no cost. In NYC NYU Dental School does plenty of dental work for free, while others are charged perhaps around 1/3 or so of the cost of a regular dentist. Imo you should start having the fillings that are in poor condition replaced first, as those are probably leaking the most mercury, and there is the possibility of getting decay under those fillings. You have 35 fillings? If so, then it would be best to have them replaced over a year or two anyway, as getting many replaced in a short period of time would give you too much mercury exposure.