tech-stitch mentioned in another thread his "turtle" phone, an ASUS Zenfone L1. I think I have the same phone, and had been meaning to share my experience with it. I'm betting tech-stitch will have tried things that I haven't.....
Background: My interest in inexpensive Dual-SIM phones stems from a thought about combining 2 plans from different providers to yield a functional 'better' plan. Another option would be to have 2 carriers on tap without carrying a second phone, or to load 2 of those too-small FreedomPop free SIMs..
ASUS Zenfone Live L1, ZA550KL.
The skinny: Factory-unlocked GSM, 5.5" screen (18:9 ratio), 16GB ROM, 1GB RAM, 3000mah battery, Android Go 8.0, Dual-SIM with an additional uSD memory slot. MSRP was about $110 when released in 2018, with heavily discounted prices frequently available in 2019. It was not a commercial success, and was not widely distributed.
The big win for me with this phone is it's dual-SIM implementation. It does allow simultaneous use of 2 SIMs, with one as 2G/3G, and the second slot 'preferring' LTE. This was critical for my desired use, with something like FreeUP or Tracfone (either on AT&T towers, for 3G voice/text), and another GSM provider in the 2nd slot for data. (FreedomPop as my main choice, but I've also used 'temporary' AT&T or T-Mobile network offers for data when I can snag one.) I've also used it switching between 2 FreedomPop SIMs just for data, and the hotspot function does work with FreedomPop. It's not the best implementation of Dual-SIM capabilities I've seen in budget phones, but it's pretty good.
Decent display. The phone is snappy enough for me with Android Go, but there is no doubt it could get pretty bogged down with more intensive apps, and there is a bit of lag on everything.
Even more critical for those who have a list of 'must have' apps is that Android Go won't run a lot of standard Android apps-- special versions of some are available for Android Go. This has not been a deal-breaker for me, but I'll note in particular that I've read some poor reviews of Google Maps Go . (I use Here Now for navigation, and it works fine on this phone.)
The phone comes preloaded with Google Go, which includes a version of Google Lite, developed as a browser alternative for countries with slow data networks. G Lite uses Google servers to process websites to compress the data, and remove unneeded information. I'd been intrigued with (and played with)Google Lite before it was technically available in the US, and liked the concept, so I was glad to see it included now in Google Go. It's very stingy on data & very quick. Some web sites work great with it, some not so much.
My disappointments: Asus says the phone is VoLTE capable, and the specs say it has T-Mobile's band 12. Unfortunately, T-Mobile did not certify the phone for VoLTE, so VoLTE will not work there. T-Mobile voice drops back to 2G. I have not done extensive testing with T-Mobile voice, but T-mo 2G voice seemed pretty reliable in my area. LTE works fine.
I also couldn't get notification dots to appear on the icons for missed calls & incoming texts. Not sure why, since there is a setting for it in the menu.
If you want to play around with Android Go, or have a need for a cheap dual-SIM phone, this is a reasonable choice. They seem to hold their value reasonably well, though. If you can snag one for $50 or under, it might be a decent option. Much over that, and I think there may be a better choice.