I've noticed several bros in this thread mention they don't take ZMA very often because of cost. There was a thread on bb.com (I believe by Manteca???) about saving quite a bit of money by buying zinc, mag, and b6 (optional) that do NOT contain calcium.
I use OptiZinc products because it contains the Zinc Monomethionine which is supposed to be the most bioavailable version of zinc (zinc aspartate would be my 2nd choice). I've used two OptiZinc products: 1 by Solary (has B6 included) and 1 by Source Naturals. I've found several brands of Magnesium without calcium: Twinlab, Now, and Nature Made.
Cost Comparison:
I've found Optimum Nutrition's ZMA for $18.99 for the 60 day supply which breaks down to $0.317 per day. The Source Natural's OptiZinc plus Twinlab Magnesium costs me $0.072 per day. The Solaray OptiZinc plus Now Magnesium costs me $0.103 per day. The "homebrew" combos are so cheap that I've been on one form or another for nearly a year straight.
~Todd