Well, you are in luck!
I just listed on ebay a pair of Ariat "Arctic Frostbiter" insulated tall riding boots with the starting price at $45 (suggested retail is $139.95).
My sister got these boots several years ago to use for the random occasion that she would ride with me. By the time that she actually wanted to ride consistently, she had outgrown the boots. They have only been worn once or twice and do not show really any signs of wear other than some red clay in the boot soles.
Please feel free to contact me on here or through ebay if you have any questions, want to see additional pictures, etc.
Thanks so much!