Primary goals is the cheapest smart phone possible that receives security updates.
Cheapest place seems to be in order:
- aliexpress
- Ebay
Walmart/best buy have refurbished/used/open box phones for pretty cheap but they're often old versions of android.
Local used phone stores are pretty sketch, at least the ones i called. They also have many times fewer reviews making them harder to vet than like ebay.
Amazon is not nearly as cheap as you'd hope. swapp.com is basically another amazon.
Aliexpression sometimes has customs fee that are not included in the price. It takes like 2 months for items to arrive. Ebay is somewhat similar, didn't specifically look into it as much.
Best method is probably to have a burner phone/old phone and order from aliexpress.
Some chinese companies seem to make pretty cheap phones: xiaomi, realme, redmi, alcatel.
Lemmy users say nokia and motorola are cheaper than avg.
Pixels are expensive but have ~6 yrs of software updates from google.
Fairphones have some hipster potential since they're easier to repair so it might be possible to make one last like 6 years, but like a new one is like 1000$
Some advice on how to buy phones in general: there are too many options so it might feel overwhelming. But just keep on browsing through them and eventually you'll start remembering things like redmi 9 isn't good enough and redmi 4 is older than 9 so it's definitely not good enough. It's easiest just to pick a brand (ex redmi) and just browser through redmi listings, then switch to the next brand and compared listings.
Haven't investigated iphone much
Cheap custom phone custom ROM guide:
GrapheneOS is more like a middle class+ OS. Only works on expensive devices like pixels and not even old pixels. "lifetime of devices will remain based on manufacturer support." When Google stops updating it, graphene stops updating it. Source: https://grapheneos.org/releases
LineageOS maintains support for old phones longer than the brand name manufacturers according to: https://www.reddit.com/r/LineageOS/comments/6gy2v4/what_kind_of_long_term_support_is_offered_for/ (there's no "stable" / "recommend" release. Nightly are what everyone uses). Looks harder to do than graphene. A bunch of the installation guides require a windows computer. Not as compatible with google play as one would hope, which can affect even basics like google maps.