What is a good, affordable, field boot?

I'm looking for something that would be suitable for schooling, and maybe a small show or two. But I'm needing it to be of good quality, an last a long time. However, I'm not able (or wanting!) to pay any more than $200. I really like the Ariat field boots, but they are way more than I can spend. I'm Womens 8, so childrens boots are out of the question.