Pro Tip: You can get an E-ZPass transponder for the I-540 toll road for free from the Massachusetts DOT
I saw that NC Quick Pass wanted to charge $20 for an E-ZPass compatible transponder (the larger one that will work all the way up the east coast). I seemed to recall that some other states give the first one to you for free – and Massachusetts appears to be completely okay with also sending them to anyone who requests them, regardless of residency. Here's where to apply for one: http://www.massdot.state.ma.us/highway/TrafficTravelResources/EZPassMAProgram/TermsConditions.aspx After finishing my application, I was informed that the transponder will be mailed within 7 days. Not bad for paying $0!