If you want a reloadable one, or with more than $250 on it, gotta deal with the ssn baloney. Unless you're an illegal.
It would be worth the experiment to put a bogus SSN in when the pre-paid Walmart/GreenDot Mastercard/Visa and see what happens. Keep the balance low so you can walk away if they freeze it. Wear a hat. I don't know that they actively do it, but WM
has the capability to do facial recognition of all cash transactions at the registers through the security cams so they can demographic/purchase-track the cash customers almost as well as the credit/debit card ones.
More of a "Cash face profile 1234A" buys Charmin every month, spit out a Cottonelle coupon at the self-serve register kiosk with his receipt-sort of thing... However, the potential for abuse goes much further obviously.
I bet illegals who don't have access to Sigo cards are already doing something like this.
Maybe just go down to "that corner" at the Home Depot lot and ask one of them how they do it and offer them a couple of bucks for their time and the info.