I'm driving from Virginia to Washington state later this month. In Virginia, I use an EZ-Pass device that automatically pays my tolls. But I understand that these devices are regional. When driving cross-country, am I best off just using quarters? Or can I buy 1-2 more devices to cover tolls across the entire country?
Depending on which route you take you may pass through at least 2 or 3 Electronic toll collection systems you can find most of them on the Government Services Administration page.
You can look at other states that have the Electronic Toll collection systems unaffiliated with other states like California, Texas, Florida, Oklahoma, Colorado, and Kansas. So generally I wouldn't bother with buying the transponders from them just keep some cash on hand for now and wait until you get License Plate billing technology installed like in Canada or Israel. California seems to be moving in that direction...