You can buy a Xiaomi phone that will last you for 4 years for less than $99, and there’s some “functional” phones for much less than that but they will be unusably slow for casual use and more like emergency devices. Then there’s the 2nd hand market…
Fortunately smart phone access is not that difficult
Then you have to work out a data plan. At least in the US, free wifi is t as ubiquitous as it is in Europe (at least in my experience).