My advice would be to just do what I did. Fill the tank with water and start getting your specific gravity up. Let that run for a week and add your sand in. Than your live rock and let it sit for a while to allow it to cycle. Alot of people say the bigger the better which is true but if you do your water changes on a nano weekly and keep on top of everything your tank will just thrive. And don't rush into anything, I did but somehow i did something right that favored me and now the tank is just thriving. esspecially once I changed my lighting which is the best thing you can do for your tank. Now with nano's you CAN fun just a fung but you will have less head acks with a sump and a skimmer.
When it comes to money with SW just don't think about it. I personally put $50 a week into my tank and try not to think about how much I have put into it. why, because at the end of the day I would rather look at my tank and watch it rather than watching tv and its extremely educational. Its the best thing I have ever done and I have no regret with this hobby.
read alot while your tank is cycling and don't even think about fish for a while. or even look at other peoples set ups.
I highly suggest this site for find tanks similar to your size and see what set up's they are running
http://www.nano-reef.com/