Just browsing through K-Mart Indooroopilly and found this rack of mens T-Shirts reduced from $6 down to $3 on Clearance. Just the typical Bangladesh made cheap shirts with silly generic slogans & logos ranging from Boxing to Football & Cars to Motorbikes & Surfing BUT there's a decent range of colour combinations, they're actually made pretty well and they have ALL sizes from Small through to 4XL and loads of stock in each design! I bought three Large shirts and they fit really well and feel great on, just as good as branded shirts that cost 10+ times more. They also had plain coloured T-Shirts for $3 and I assume these would also be available at other K-Marts too.
Note: They did scan as $6 at the checkout but I showed them the above pic and they apologised then reduced them to $3 so probably best to save the hassle at the selfies and go to a 'personned' checkout instead.
Pretty sure they're the same price at a few stores in Vic too, so probably nation-wide.