They really shouldn't be hurting for money, not just for clothes but for anything else as well. Cleaners, Fixers, and other kinds of hitmen (yes, they are all subtly different) tend to earn big money for each job, often making enough off a single hit to let a small family live comfortably for more than a year. (Even after handler fees, ~¥600000 should be about average per contract) She works in that field (or claims to at least) and seems to be doing a hit almost every day, while he's working a regular job that should be paying pretty nicely as well, so they should have enough money to not only buy whatever outfits they want but even to buy out the entire complex if they wanted.