Instead it seems that Capcom is making it a challenge to get them, which we guess can also double up as bragging rights. According to Capcom, “Every month, there will be at least one unique costume like a Crossover Costume up for grabs, which can only be obtained by playing Extra Battle Mode with Fight Money.”
There will be four challenges held per month (one per week) that players will have to participate in. Each challenge attempt will cost players 2,500 Fight Money, which means that assuming you don’t fail the challenges, each costume essentially adds up to 10,000 Fight Money. As Capcom notes, each challenge is time exclusive, so if you miss out on it then your chances of getting that month’s costume is pretty much out of the window.
There are currently three challenges planned that will span 3 months, with the first kicking off on the 27th of February. The schedule and details for the challenges can be found on Capcom’s website.