Hello! One idea that you can do to make Terra's shoes can be quite simple and affordable. Try checking out a thrift store for some boots, and then paint them red and gold. And if you feeling like spending more time into your boots, you can hand stitch the beads and sequins in them. That's what I had to for my Terra cosplay.. They were originally brown cowboy boots being sold for $3 at my local thrift store: http://www.cosplay.com/photo/3038596/
Sequins are usually pretty cheap, and so can 'small' beads depending where you get them.
Good luck with your first cosplay!!
And it's great to see Terra be cosplayed!