Durability is important to me, as the wife and I use trekking poles year round in snow, talus fields, soggy river valleys, etc. We use the basic black diamond fliplock aluminum poles. My set has nearly 1000 miles on them (from my own use, I bought them used), and I certainly don't baby them. The fliplocks are easily maintained in the field. I prefer the black rubber-type handles to the cork, but I doubt it makes much of a difference.
A quick search on geartrade shows a set for sale at $35. I have no connection to the seller.