...you've got questions, I've got answers.
As to whether Tracfone uses Sprint, the answer is a resounding No. At least as a primary carrier. The biggest CDMA carrier they use is Verizon. And the reason they have small coverage areas for CDMA is probably to get the cheapest minutes from whatever carrier they're buying minutes from. So if you want the full network as non-roaming you sign up on that carrier's prepaid or postpaid plan...the former if they have one. Anyhow the fact remains that the only thing Tracfone uses Sprint for s if you're roaming of of them, which is very rare.
And for a quick comparison between the Nokia 2126 and the 2600 I'd be inclined to say that the former is a better phone for less money. Though this is probably because it's newer. But I think that the 2600 is slightly more customizeable and it's GSM...just depends on what network you want.
As to whether I can keep providing 120 minutes for $12, 60 minute cards for $10 and a higher minute amount (may be as low as 140, may be as high as 200) for 10 cents a minute on Tracfone, I can do it just as long as can get the refurb Nokia 1100 with 60 minutes deal off of Tracfone's website. And bar that things will get more expensive but 120 minutes as far as I can see will always be cheaper my way than by using a normal $30 card. Anyone interested?