As I learned how to make multiple HSTs way back in the days before there were commercial products to speed the process, it always surprises me how many people are willing to spend money to make that which is so easily done without props.
Try this:
Using 2 fat quarters....or two fabrics of any matching size.....layer them right sides together and DRAW lines to create squares ONE INCH LARGER than the finished HSTs you want.
Once your square grid is drawn, draw long diagonal lines thru every other square across the fabric.
Go back and draw long diagonal lines in the opposite direction thru the squares you avoided the first time.
Sew 1/4" EACH side of EACH diagonal line.
Press the whole fabric piece.
Cut the piece apart on EVERY drawn line.
Press open.
Trim to size. Viola!
I've made a few as 8 HSTs and as many as 80 HSTs at a time using this method.
Jan in VA