Apparently, Oakland's historic preservation guidelines are nationally famous
"Unfortunately, the prepaid phone situation in the United States is pretty backward. Yes, you can buy prepaid SIM cards here, but it's a more convoluted process than it is in many other countries. For example, while most U.S. carriers require you to buy a phone to get prepaid service, carriers in other countries don't have such restrictions. I've been to a few countries in Europe and Asia where I purchased a SIM card from a carrier store and then popped it into my handset I brought from home. They didn't care whether I used one of their handsets or not; it only mattered that I was purchasing service. Other countries, particularly those in cell phone-loving Scandinavia, make it even easier by selling prepaid SIM cards in vending machines.
"There are a few places in the United States that sell SIM cards without a phone. I would check a few wireless stores when you get to Delaware and see if they have them. Best luck in third-party cellular stores not operated by a carrier.