Easiest glitch in the world, found it doing attempts by accidentally forgetting to pick up the permanent markers in the arcade bathroom. Just do the following and never have to buy anything ever again:

Step 1: enter the second stall in the arcade bathroom Step 2: Open the gift box and get $75 Step 3: Immediately leave Step 4: Repeat steps 1-3 Step 5: ??? Step 6: T i m e s a v e

I've been screwing around with it more and it saves around 30 seconds on top of any time you would have spent going to pick up brooms and cameras after dungeons. You can also use this to hedge your bets on how lucky the run will be by doing the glitch less, getting less money and banking on not that many encounters where you need the cameras in backstage, because this game needed more RNG in it.