Im interested in learning piano. I wanted to start on an affordbale keyboard.?

Ive had people offer me a variety of Casio CTK's and things like that. At first I thought any ole keyboard would work to learn piano but they say lil cheap ones dont play chords, more than one key etc. I have no idea what any of that means as of yet. Just looking for advice on how to start as well as any recommended self teach books or whatever.