Based on my purchases there, not sure I'd call Greentech a low cost store, but never mind that.
The flashfoot2 are about $15 each, you need 2-3 per panel, more in high wind zones (I had 16 for 6 large panels).
Rails are about $4-5/foot ($51 for 11 feet, or $29 for 7ft), so for a single 42"...