Hey there,
I'm in the middle of putting together my first Fett, so I welcome you on this kick *** journey
What I would recommend is that you do as many who start do..at the beginning. Research, research, research. There are many threads on here for how to start out, although I have had issues from time to time navigating this site for specifics.
A Boba Fett will put you anywhere between $2000-$5000 depending on how much you want to spend.
http://www.thedentedhelmet.com/f22/new-tdh-read-about-how-much-you-will-spend-17421/
I've seen threads from people that craft their own, but my advice would be to find reputable sellers from here to get your gear. If you're not into painting, there are many artists on here that can be commissioned for work, but again, that all depends on how much you are willing to spend. There is a thread on all the distributors here ...good thing I bookmarked it
http://www.thedentedhelmet.com/f20/new-member-questions-needing-direction-rotj-build-39282/
If you're going to order materials, order sooner rather than later as many artists take time to produce such quality work.
As for Rubies...I don't really have much to say about it. It really all depends on how deep down the rabbit hole you are wanting to go. What's your budget? How accurate are you wanting to go? There are parts where you can probably sacrifice a scratch build to save money (there are many tutorials for boots, capes, EE3s, etc.) but in my experience in costuming, sometimes (for certain parts...and me being a perfectionist)...it's better to save up and buy the pieces needed. Sometimes in building the scratch build items, you're never happy with it, and spend almost as much in materials as you would buying it professionally done. But the satisfaction of building something that you can be proud of is unmatched. For me, I could never build something screen accurate that I would be proud of, so I get that satisfaction by following all the tutorials and spending the time and research to get the costume to where I'll be happy with it.
Best of luck with your build. Hope to see a build thread soon to follow your work!