Here's a thought to maximize coverage (assume AT&T coverage is better than T-Mo in your area)...
Dual SIM Phone
SIM 1 FreeUP for voice
SIM 2 Mint for 5GB LTE data that also allows tethering
At $3.36 for a months (after free shipping code and eBates), you can't beat this.
I am not seeing the $20 cash back on ebates currently, very surprised, plus wanting to get one more. hehe
I was betting on either Christmas or New Year's Eve return.
Guess there was no "another $20 cash back" deal.
I was keeping eyes open, too. I don't need another Mint line, but another $20 cashback offer would have let me extend my Mint access date by 45 days...... at roughly $14 to do so (with $10 cashback), I decided I'd be smarter to put the money towards a line that was sustainable at around $10/mo.
I'm going to have a little fun with the Mint plan this weekend-- a road trip to an area that has marginal coverage from everyone except U.S. Cellular. We're taking Mint (T-Mo), FreedomPop (AT&T), Tracfone (VZW), and Sprint, and seeing which works. I probably won't be able to prowl the countryside looking for dead spots, though.
I bought two of of the $20 promotional SIMs on Dec. 31 and plan to activate them on Feb 1.
There’s a chance (unlikely, but possible) that I may receive 8 GBs per month, given the following development:
I got an email from Mint letting me know about the upcoming data increase on their plans. It included this:
"What does this mean for you?
After January 29th, your current plan will automatically go from 5GB to 8GB on it's next monthly reset at NO charge."
Nice.
As stated in their press releases, Mint Mobile started their increased data packages today ( e.g. 8GB of data@ $20 per month)
This is one solid and classy company that deserves to do well. Their commitment to every day value is heads and shoulders above the competition. And their marketing approach is clever and fun.
My entire family is now on Mint Mobile.
I'm sure most of you are aware that Mint Mobile is owned by Ultra Mobile.
Here's a profile of the CEO from two years ago. ( I like this guy)
$20 for 3 mo deal is back! 
eBates has $10 cash back and $5 off (=free) shipping. IRFREESHIP
Correction, cannot use IRFREESHIP because you have to enter CHUNKYTWEET to get the $20 price... so $18.36 total (after eBates $10 cash back) then...
So, if still 45 day activation limit, that would mean activating this SIM on the ides of March.
Shipping is free with Chunkytweet. Mine shows $25.24 then you get $10 cash back from ebates. If you go via the cellnuvo app you get 8880 silver or something like that and if you start a new ebates account you get $10 bonus when you spend $25. So all in all still a money maker provided you have space to sign up for a new ebates account.
So looks like still possible to get 3 mo for $3.36 by getting someone else to sign up for a new Ebates acct. Nice!
Some thoughts about the current Mint offer...
The linked Slickdeals thread has several people who asked MINT CS about the 45-day activation requirement, and the info was mixed. One CS agent said the 45 day period was hard fixed and could not be extended. 2 replied that activation after 45 days was fine even without customer service intervention, but that any guarantee or refund offer would not be honored past 45 days. One SD member reported waiting 60 days to activate, with no issue.
Ebates cashback could carry some risk on this offer. There seems to be a generic warning that using any coupon code not provided by Ebates might make the cashback offer invalid. (The previous Mint $20 offer did not require a code to reduce the price to $20, and this coupon code does not appear on Ebates.) But I see today a couple of SD posters saying that the cashback did show up on their ebates account.
[EDIT TO ADD-- a couple of forum members here had the Ebates cashback post just fine, as reported just below.]
It looks like TopCashBack & BeFrugal both have the same $10 cashback offer-- and possibly others. The SD thread has a couple of posters who had problems with TCB working, and no reports that I noticed of BeFrugal. BeFrugal did work fine for me the last time this was offered, although it took a lot longer to be payable than ebates did.
There is one eBates offer that does not require a code.
For a limited time, get 2 months Free when you buy your first month. + $10.00 Cash Back
Exp. 02/27/2019
My total $24.58 this time. $10 cash back would make it $14.58 for 90 days.
Can't get it to work. Doesn't apply automatically and there is no code that I can find.
I did use chunkytweet code for a family member yesterday and the ebates bonus, new customer bonus and cellnuvo silver bonus all posted.
Oh, yeah, I had to enter the code too... guess eBates messed up the description on that offer - not giving us the code to use.
According to https://www.prepaidphonenews.com/2019/02/mint-mobile-running-promotion-for-3.html
the current $20 offer will run through March 1, and won't require the code entry to get the discounted price after the Mint ad runs on the Super Bowl.
Ah... so too early thus had to use the code.
"This promotion will run from February 3 and ends on March 1 at 2:59 AM."
Would this work to renew an existing Mint number that's plan is about to expire?
If not, what would be the best option to obtain the best price for a Mint line that's plan is expiring?