My aunt has Safelink Wireless. She goes to the Tracfone website and purchase minutes and uses bonus codes. They offer these types of denominations with bonus minutes for only Safelink: 9.99 30 minute card for 50 minutes, 19.99 60 minute card for 100 minutes, and 29.99 120 minute card for 150 minutes. She doesn't have DMFL so I can't comment on that aspect.
My aunt usually gets the 9.99 card for 50 minutes and the extra offers of 10.00 for 60 minutes which give her 100 minutes and 5.00 for 30 minutes which give her 50 minutes. So about 25.00 for 200 minutes. Maybe if someone has Safelink with a DMFL phone they can give some extra savings pointers.
BTW, you have the option of using the phone number or serial number.
19.99 Even More Plus
200 Whenever Minutes
Unlimited Mobile to Mobile