iphone 5S under $100

There are three options:

Switch to Boost

Bring in your current account number and password and move your current phone number to Boost (Spring network).    You would need to pay $50 for the phone and $50 for the monthly plan for a grand total of $100.   The $50 per month plan has unlimited calls, texts and 4G data.

Start New Service

The phone would cost $99 and $50 for the monthly plan, which has unlimited calls, texts and 4G data.  Total you will need is $150.

Have Boost and want to upgrade

Assuming you are eligible, the cost will be $99.