Tello is running a new customer special 7/4-7/6.
Sign up for any monthly plan (straight PayGo doesn't seem an option for this), and Tello will credit up to $17.76 against your first month cost. (It looks like any unused amount goes away.)
The offer is on the main page at https://tello.com/
If anyone isn't familiar, you can change your plan easily whenever you need, either upgrading or downgrading, including shifting to PayGo if that ends up working better for you.
If you're interested, make sure you go to the referral thread and pick a referral code to use during signup-- this should get both you and the the referring member 10 Tello dollars that can be used later.
My extended family has several monthly Tello plans, as well as a couple of emergency phones on PayGo accounts (which has saved me from being without a phone a couple of times.....)