Commsec won't allow you to buy a initial parcel less then $500, BUT, they will let you add to an existing parcel with less than $500.
My theory is if you own $500 of shares you will be able to add your inspecie
I have not tried, but that is my interpretation - the minimum $500 initial purchase is due to limiting the amount of unmarketable parcels
DYOR - I have not tried the above and may be incorrect. My teenager boy is in that boat, and he's happy to buy more DRM (not for this reason of course) next payday so I'll report back later - probably 2 weeks
DRM Price at posting:
27.0¢ Sentiment: Buy Disclosure: Held