Not sure if you have an answer or not, but my company actually does this with apartments, so I have some unbiased opinions:
1. The best company to incorporate is PayRange. It's relatively low cost, has lower CC % fees, and extremely easy to install.
2. Credit card readers at machines are hardly ever worth it since they're expensive per card reader, have ongoing monthly fees for support, and additional CC % fees
3. Laundry Card is my favorite since it usually means people spend more. They have to populate the card with either cash or CC/DC, and then once it's on the card, they use it to start the machine. This way, you hold onto the "float" or the money left over on the card after they spend the initial amount.
- Example: I (the tenant) put $10 on a card. I spend $2 on washer and $2 on dryer. If I was doing #1 or #2, you would receive the proceeds of the $4 after fees, but with #3, you would receive $10 less fees (if they paid with card), and then the remainder $6 would stay on their until they use it, or redeem. Think of it as a gift card for the laundry room.
However, BIG CAVEAT, with only 1 set of equipment, I would suggest #1 highly. As long as your tenants have a smart phone, they'll use it. #2 is a close second, but #3 is really only for big apartment complexes.
Hope this helps...
AERC Laundry Solutions