Look back at rockys_pride's post on what you need the stock tank for. You need to have premixed ph/temp adjusted saltwater ready to receive the livestock and rock, so they don't die while you're getting the tank ready to go. You can find sand for around $1/lb, salt mix can be $1 per 4 gallons. Changing filters through the year, test kits, food, etc.
Check this post out, and read all FAQ pages that follow it:
http://www.wetwebmedia.com/movingaq.htm
wetwebmedia.com talks about costs for electricity and water use costs. And lots of other things.
Also consider this tank would weigh at least 1200 lbs and may need to be on concrete slab or reinforced flooring on the first floor. Your landlord may not allow it due to structural issues so make sure you're covered there.
If you're worried about money and have this many questions about how to pull it off, you may want to pass on this and find an established biocube to get your feet wet with. Especially since you're worried about how much money you will spend. You could have a friend help with the heavy stuff (or 2-3 friends if this is glass and not acrylic), but you should have at least one person who knows what they're doing and has SW (and possibly move) experience to help.
