The "Stuff the Duff" T-shirts show a caricature of Duffy being dumped headfirst into a trash can, surrounded by bags of money on the ground.
Duffy resigned from the Conservative caucus last week after it was learned he had accepted a cheque for $90,000 from Nigel Wright, the prime minister's chief of staff, to repay a Senate housing allowance. Wright resigned from the PMO on Sunday.
"This whole business with the $90,000 from the prime minister's chief of staff probably was sort of the turning point," said T-shirt creator Lloyd Kerry.
"But right back to where he paid back the $90,000. To me that says, 'OK, I paid it back. I'm admitting I'm wrong, because I shouldn't have done it in the first place.' To me, that's when he should have resigned."
Kerry also created the popular T-shirts with the letters, PEI EI PIs, inspired by recent employment insurance sketches on This Hour Has 22 Minutes.
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