Do not waste money on cheap skimmers either. I got a free one from a friend of mine who paid $55 for it new. Having done research prior to setting my tank up, I found the skimmer is useless.
It was free so cannot complain but am looking at about $125 for one rated at 65g or 2x my tank volume.
Live rock is cheaper in the US than Canada so I would look at paying around $5-8 a lb for that, you dont have to get all live rock, dry marco rock is cheaper but you will still need a lot for that tank...I paid including shipping $135 for 40lb's and $14 for 2 small pieces of live rock (2.5lbs)
So there is about $280 straight off on just a few essential pieces...factor in powerheads, heaters (you need 2 or 3), saltwater test kits, buffers perhaps and live sand. It adds up quickly.
As mentioned, save and continue the research, it REALLY pays off...almost 6 months from when I started researching until last weekend when I got the tank going. The research paid off though as putting it all together was a breeze because I knew how to do stuff in advance.
If you are going to have a sump, you can also spend the time building that, if you have it already.
Patience is the key and you will enjoy it 100% more if you do the research now and not skip over things.
Keep a little journal on stuff like treating algae outbreaks etc, fish care, etc.
Hope this works out for you