There's no guarantee that same car will still be there for the trip home. Someone else can grab it in the meantime. You can reserve a car 30 minutes in advance, but that won't work if you're going be at whole foods longer than that. You can just hold onto the keys and not "end the trip" but you will be charged for that hour that you're holding the car. This is a problem. If you've got several bags worth of groceries, you're not going to want to hunt down a car2go.

The charge is .41 a minute plus a $1 per trip for insurance. There are different pricing levels for 30 minutes, an hour, or a whole day. This is for the Twin Cities. Last year they provided a card you could use to refuel and they would give you free minutes if you took the time to do it. Their app shows you the fuel level of the cars in your area. People would find ones that needed fuel and gas them up just to get the additional minutes. I'm sure having 6 cars being parked in front of the same guy's house wasn't a desirable outcome even if the tanks were full.

Now it looks like you have to pay for any needed gas yourself and send them a picture of the receipt. The way the system is intended to be used though, it's not likely you'd need to get fuel.

They will also "rebalance" the cars as far as where they are parked. I got a bunch of free introductory minutes and over the course of week or two, used them up just getting a feel for the cars and the system. After I burned through my minutes, I noticed the cars would just sort of show up in front of my house overnight. Maybe it was a coincidence, but I think that was intentional and the results of analyzing their trip data. I'd bet anything that heavy users don't usually have to go far to find a car. The cars come to them.