I have found I can get net 10 service cards cheaper than straight Talk...
Go GSM! Switch phones on demand.
Thanks. I figured you'd need to do it on a month end and get a new SIM. Wish I had done the math before. A Straight Talk monthly plan (with no fake order address) is a little over $49 for me. While Net10 would actually be a little under $47 because they are often 7% off at CallingMart and you simply don't pay sales tax there (though I know you are supposed to submit use tax I guess after the fact). So the recoup cost on a $15 SIM is 8 months, not worth the hassle.
I am planning to switch another line, but this time I think I'll go straight to Net 10. I'm assuming their $45 discounted auto-refill plan is taxed, which makes them exactly the same as Straight Talk in worst case, and better if I can get discounts off face value from anywhere else.