either you get a pixel 2 (support ends Oct 2020)
https://slickdeals.net/f/13867289-go...SearchBarAlgo1

or try your luck with a chinese phone (which would come with android 10, but no more updates after that)

a refurb iphone 8 may be found around $250, which gives more updates than other android phones at this price point
https://slickdeals.net/f/13857293-vi...SearchBarAlgo1