you don't need a protein skimmer on a 30. I have never run a skimmer on anything less than 40 gallons. My first tank was a 20 and it never saw a skimmer... neither did my 33.
Anyway CC is a pain in the butt. sure, it's cheaper, but you're going to pay for that in other ways. If you want the more economical route, go to the local home depot and pick up a bag of aragonite sand for under $20. One bag should be enough for your tank. I also recommend you get rid of the UG filter, and instead maybe put an AC mini on the back to catch the floaties, and then add 2 powerheads.