Buying phones for farming

I remember seeing a post ages ago, (some time last year) about buying 2nd hand phones for farming.

Some guy who sold 2nd phones posted his site. I can't remember what the site was but I bought 5 LG phones off there for $10 each which was extremely cheap.

I was thinking of buying more 2nd phones from there because everywhere else is too expensive.

If anyone knows what I'm talking about that, that would be great :)

Otherwise, does anyone know where else I could phones for less than $20.