@maindaf16 -- since the size is exactly what you are thinking about, you might want to consider something like this from Ebay:
https://www.ebay.com/itm/Quict...
There are any number of different sellers offering these things, none of which do I have any connection to - but I did buy 2 smaller ones, 7x15x7, a number of years ago and in my mind they are about the best bargain I ever got. The covers on mine didn't last very long (they were obviously not UV protected, but the ones that are listed now all specify that they are UVP), but one of the frames I've re-covered by adding some wooden framework, and the other I covered with "remesh" (concrete reinforcing wire) and use as a trellis for cucumbers, squash, etc. (I also shortened the trellis up by one section.)
