I really hope that the costume looks cheap.
What I mean by that is, I hope that it looks like something Matt Murdock could have plausibly made on his own without access to expensive machines or materials.
I don't want this for realism or believability, I want this for thematic reasons. Matt Murdock is the underdog. He's a working class Irish-Catholic lawyer who works civil cases for small businesses and families suing huge companies essentially pro-bono and moonlights and a public defender. His arch enemy is a wealthy and corrupt businessman who employs half of his neighborhood. He is the living embodiment of lower class, Irish-Catholic, inner city liberalism. His costume should look homemade. Especially if, as others have suggested, it incorporates his father's old boxing equipment.