I bought boots really similar to those last night!! Been looking for a while to, so here is my 2c.
Mine were slightly better, higher roll on the MF, picked mine up for 30mil I think it was. I would list it for about 30-35.
The way to search for comparable boots? Those boots either roll something like 70-100 dex or 170-200 dex naturally, all res, move speed, armor are all natural rolls. The MF is the only random roll there. First filter all the low dex boots, so set your dex filter to 170. Then add a filter for MF, leave it blank. That should narrow it down to about a page worth of results. Maybe less, I bought the only pair of boots at the time which had MF of at least 16 and met those requirements.
That will give you a good idea.