Pretty much anything from the last two years will suffice (or even older).
It depends on what you're doing.
ie. I'll often be on 4-5 poker sites
at same time & might have a dozen to fifteen tables/tourneys running, along with other software, emails, trolling forums, listening to music, etc. etc. & my laptop is nothing special at all (pretty basic actually). My 17"Acer (couple yrs. old) is fine for this, 4GB Ram & mediocher processor.
I also use an old Dell 15" (with extra monitor) & it too has no problems running multiple sites/tables, etc. & has just 2GB Ram & an Intel Pentium processor that is ancient by today's standards.
What I'm saying is > anything will likely suffice. Probably want to go with 4GB Ram though (minimum if poss.) & semi-decent processor.
Some of the newer ones I see at Walmart these days typically have min. 4GB Ram, good processor & are REALLY CHEAP! (as in $400 for a 17", $325 for 15", HP, Dell, Toshiba). Any of them would be more than good enough imo.