The first product we've ever covered from Favi, Screen Portfolio Case with Bluetooth Keyboard for iPad Air ($40) has a notably low price for the features it offers. It's made up of three different pieces that can be assembled and deconstructed as necessary. First, there's a thin plastic shell that snaps onto the back of the tablet, leaving wide, off-centered openings and a hole over the Apple logo. A posable plastic arm uses that hole to latch onto…