I've owned my Nokia 3595 (through T-Mobile) for about 10 years and still love it. It is tough, easy to use, and the stand-by battery life still lasts about a week. Both reception and audio quality are excellent. I've long since stopped my monthly plan and pay $100 a year for 1000 minutes (and have never used them all). I'm a very light user, saving it for quick calls and emergencies, so I don't really need anything more. It feels great to save money and have a dependable phone on hand.
Obviously it is not for everyone in this age of do-everything smartphones, but it suits my needs perfectly. I would also recommend it for parents who want to get their kids a nearly bullet-proof emergency phone, but want to save money and not "distract" their kids with internet access and tempting apps. As of this writing, it can be found unlocked starting at around $20. I'm considering picking up another one because my wife prefers my 3595 to her more modern touch screen Samsung. Nokia hit a home run when they made this model, and the ball is still in the air.