I usually use Botanica roll-on, which i get from Coles or Foodworks, but i just found this one: http://www.natures-gate.com/shop/showitem.asp?ProductId=45775047&menuId=149&withLinks=1 at Priceline - it's certified vegan & organic, comes in a few different scents, & Priceline has a two for one offer on the range atm!
The Botanica is still a tad cheaper though, & is a more 'traditional' roll-on, where as this one is a little different.
i use Riva, it smells nice. I got it from Sam's Warehouse, its $2.50 but i will try the Botanica one!
Here's a link for it, in case you aren't sure what to look for: http://www.bodycrystal.com.au/Body_Crystal_Essentials.php
It's the one second from the right, though they have changed their packaging now, & the container is shorter & fatter, though still the same ml.