Tire Bubble problems of the 2001 Toyota Camry

On 9/24/08 I went to town fair tire and had four tires replaced at a cost or $539. 12. I was told yokohama tires were the best and had the best mileage up to 80,000 miles. At that time I had the four tires replaced with the mileage on my car at 74,000 miles. On 6/3/09 I brought my car which now had 81,000 mls. On it with a bubble on my tire and had to replace it at a CA cost of $134. 51. Five months later on 11/02/09 I went back to town fair tire with 83,000 miles on my car and another bubble on my tire. I have been driving for forty two years and never had a bubble on a tire and in a little over a year and less than 10,000 miles I have had to replace two of these tires because of bubbles. Town fair tire says its my driving, I say there is a defect in the tires and I do not feel safe in my car. I can not afford to replace them again. I am on disability and do not drive to often but I like to feel safe when I do. I would like these tires investigated. $800. 00 for tires a year is very expensive and I don't know if I will have to spend more. . The tires are yokohama avid trz id cc208213308-4208-4408 I would appreciate an answer as soon as possible. Thank you for your time and consideration.