Looks like a nice enough board, but it will require some work.
A Teensy will cost you about $22 shipped (US) and that will take a bit of wiring.
The Model F XT is a great-feeling board but the layout is dreadful. If you are picky about appearance, the plastic on the Model Fs is harder and more brittle than on the Ms, and there is a shiny substrate with a separate "pebbled" layer on top. The seller refers to "paint peeling" at the corners, but it is actually delamination or spalling.
Until recently (and I have not tracked prices in the last year or so), these could usually be bought for $20-40 + shipping.
Unless you know what it is and want to make a project out of it, I would say "pass" unless it was practically free.
