It's been centuries since we used a parking meter the way it was originally intended. Neither my husband nor I keep change on us anymore. We do use the parkmobile app, but of course it is not universally used in every city. So when we were in Bethesda today looking for a mirror for our new tiny closet bedroom, it was impossible to find parking - except at a very expensive parking structure or a parking meter. We slipped in to a parking space and started reading the directions. Obviously there are multiple ways to pay these days - with coins, with a scanner, with a credit card, using the mcdotpark.com website, with the mcdotpark app, or by calling. So we went ahead and used our credit card. You could increase or decrease the allotted time, and then ok the transaction. Since we didn't know how long we would be, and then maybe get lunch on the way out, we left it at two hours for $3.50. We ended up using about an hour, but we did learn that whatever the parking meter is, there will always be a way to pay for it.