Hello itZme and welcome to Frag Outpost!
What kind of corals are you planning on keeping?
You don't need to use all live sand. Really, you could use all dry sand and add handfuls of sand from other peoples tanks. Within time it will all become live sand. Bacteria and pod biodiversity is important, so getting live sand from more than one source (assuming it is free of red bugs, parasites, and other undesirables) would be beneficial.
There are alternatives to live rock as well. You could use dry rock as a base and use the nice decorator rock as the outer or top layer. It will all become liverock soon enough.
Check out
HiRocks.com for dry base rock. I've never used it but have heard good things from people who have.
There is also the aragocrete method. garf.org has a good article on how to do it. This method is very cheap to do can can take a few months before it is ready to add to your tank. If you want more info I can dig up some articles for you or try searching Google for "diy live rock" or "aragocrete".
For cleanup crew and macro algae I highly recommend
FloridaPets.com. They usually have a great selection and always have great service.
Hope this helps.
Can't wait to see some photos of your tank when you get it up and running.
-FragOutpost