I have a Swedish and an Australian SIM card. Each of which cost less than US$ 10 and included a bunch of minutes and free or nearly-free (international!) texting and cheap and easy-to-get refills. Both of which "just work" every place I've tried to use them.
Except one. The US... where they want 10 times that much just for the SIM and they can't even guarantee that it'll work in both Florida and New Jersey!
When I went to Sweden, I found the first news paper stand I could find, bought a SIM card for US$10 and got US$15 in credit. Yes, they gave me 5 dollars more in credit. And the best part, my pre-pay Swedish SIM card worked Internationally, I tested in Japan and the US. The refill process is simple as getting a code printed receipt from a number of places, you text the code and you get refill confirmation. All your minutes are valid for a year upon refilling, including your previous minutes, even with the cheapest refill amount. They even offer campaigns such as free internet days, 3000 international SMSes if you refill with $25, and etc.
US carriers such as T-Mobile, offer Prepay, but the damn SIM only works in the US, will not register internationally, require a purchase of the SIM at double what I paid in Europe without credit on it, and expires in mere months.