Planted Tank Guru
Join Date: Sep 2006
Location: Northern California
This is a loaded question.
Low tech = sand from Home Depot. $20.
High tech = depending on substrate, size of tank, etc....ADA AS could cost $200. You could go all DIY MH or spend money on a Tek, etc...
If you do a fish-only SW tank, that's probably cheaper than a high tech freshwater planted tank. If you do LPS that might make a difference. If you do many SPS w/ the full works of an automated controller, calcium reactor, large skimmer, etc, you're looking at spending big bucks.
Too many factors that play a role to give you a nice, simple answer.