Works for Pixel too, but doing this with any of the other android brands would turn out more expensive.

I think it might work with expensive Android phones if you do that every 6 months or even less... (keep the box and phone intact of course).

depends when you buy... I sold my last phone for the same amount that I bought it for, a year later (bought it on sale and it was not a Pixel or iPhone)

which phone was it?

Samsung Galaxy J3... not a flagship phone, but I bought it and sold it for around $50 ... another example could be the LG X-charge that was sold by Comcast for $0.01 last year on sale (no contract) and it is $180 now