Personally, I love TracFone. I have never had any problems. I bought a new phone online a couple of months ago and I got free double minutes for life. I loaded a one year, 400 minute card with a code for 200 bonus minutes. I bought it and loaded it online, and got the option to add another year for $50, so in the end I got 2 years of service, 1000 minutes for $150. Perfect for me!!
If you sign up for email newsletters, you will get codes via email, also, they are always offering specials on their website.