Now that Maryland has joined a number of other states in requiring a deposit when signing up for the E-ZPass electronic toll system, a number of people are looking at their options. Many are simply swapping the transponder between cars when the device is needed, rather than getting two or more.

Adding to the cost of the deposit is the fact that you have to keep a balance on each unit for each account; that means tying up money that can be used for other things, such as gas. Some companies are even marketing devices to make the swap easier.