Depends on the brand of tankard what lighting and pumps and filtration you wanted to use my 120 gallon Lps tank cost me $1300 to get it all setup and running
Depends if your thinking new or used. New could range anywhere from 300-1,300 depending on what all you want. I got a 50 rimless cube with an mp10, skimmer, led and LR for 350 on CL.
I posted on another thread. Check out petsmart on black friday. They will have all ensembles for half off. I am going to pick up a 75g tank, stand, and led light for $250. Seems like a good deal to me. Keeps me from getting something used that may have problems.
A couple hundred. I read in another thread of yours you have only 700 to spend?
I think it should be enough. Lights will cost you most depending on the type, you can look on craigslist or something of that sort to find a good deal on a 40 gallon.
Read this: https://www.reef2reef.com/forums/reef-aquarium-discussion/181799-my-five-mistakes.html