Simple was/is a dressed up version of a prepaid debit card with a good mobile app and a good web ux. Typically prepaid cards net $1-$4 per active user per month depending on the level of fees. An active user is someone that has loaded cash onto the card. So if Simple had 100,000 customer which could translate into 100,000 loaded cards, its gross revenues would be between $100K-$500k per month (1.2-6m per year). My guess is the 100K number is simply customers that ever signed up for it and that their active accounts (loaded cards is much much lower). Kudos to the Simple board, investor and team - selling at that sort of price is unbelievable. I would happily work with any investor who could help me get that sort of valuation for my companies.