Emoryl

After experiencing a flat tire last week, I took out the Pony tire only to find it had a huge blister on it. I had never used it before. I went to the local Firestone store as suggested to me by Firestone headquarters. He was very helpful but advised me that the size Pony that I needed, T125/90/R15 was no longer available. He said he would give me a new full size tire but I had to purchase a rim at $40.00. That would be OK with me but this tire will not fit in my spare tire compartment. It would stick up at least 4 inches and would use up some of my precious trunk space which is very limited to begin with. Does anyone know where I could buy a new or used Pony of this size? Or does anyone have any other suggestions? Thanks for your help. Emory Leonardi