Try Abercrombie and Fitch. They have fitted shirts. Also try threadless.com. Those shirts are slim fit. I'm pretty sure Volcom and quicksilver sell fitted shirts also. Try dry fit shirts as well. I hope I answered you question : / Good Luck!
Try David Jones. Or clothes stores in Claremont, Subiaco or even Cottesloe
I think you meant 2 shirts for 5.50 dollars. If so, 5 shirts will cost 5.5 X 5/2 = 27.50/2 = 13.75 dollars Note that if the offer is buy 1 and get 1 free, the above will not work out. You will end up with either 4 shirts for 11.00 or 6 shirts for 16....