Alright, so AppyLover just introduced me to a great deal on Surcingles, so I've started a thread to post your great finds! Let us all know where the good stuff is, especially if it's a good price!
I just found 2 regularily priced $35 lunge lines for $10, I'll try and remember where, because they're amazing quality.
Other than that, here's another great buy:
Training lunge cavesson for under $20!