Yes you can buy mulitple parcles of small shares in one day and it is classed as one transaction. This is also the same for a sell as long as one stock.
It does cost a little bit (from memory about $40 per trade for the day).
What I do not like is the difference in trading capability.
eg pay a bit more and be closer to the action (ASX servers). Now this to me creates different classes of trader/investors.
