i would say the two easiet ways are eitehr ...
make wooden frames out of 1 x 1 pieces of wood for each side and then staple sscreen/wire mesh (crickets can eat through the non metal screen just as a tip). then just hinge the whole front end piece.
the other is a bit mre difficult to find the parts ... i dont remember where online it can be found or if you can get it not online but i purchased a few years ago what are these j shaped metal clips and a pair of pliers that fit the clips .. you just take some heavier duty screen or pvc coated screen (such as those expensive iguana type cages in pet stores) and then crimp the clip around the edges of the two screens and form a box.
hope that helps some