I have a 65 gallon aquarium what would be the least expensive way to start a marine coral tank?

If you are worried about money, not have a reef aquarium. You need at least $ 1000 just to start your deposit. This does not include the corals and fish. The largest expenses will be its light and live rock, followed by their pumps and skimmer. If you really want a reef tank and are on a budget, check out the smaller nano tanks, as a gallon 12 or 24. You can usually find cheaper used and the only major expense would be to replace the bulbs w / new ones. You do not need a lot of rock alive, 15 to 30 pounds, but will let you keep a few small fish, inverts, and a few corals.

65 gallon Tropical Community Aquarium