Would anyone recommend a recreational, sit-on-top kayak that I might pick up used? It will be a first kayak for a geezer who loves the water. Ponds and lakes only!
Or your local Craigslist can be searched for used boats.
There's a Wilderness Systems Commander 120 listed for sale in the pNet classifieds. That kayak is in Florida.
Where are you?
We could recommend decent used kayaks from Craigslist if you share the city/state where you’re located.
Old standby kayaks
Most of the Ocean Kayak models made for day paddling and touring are good bets - scupper pro if you find one is good, prowler, etc. Scrambler is a good shorter boat. Frenzy is a good short sit on top for rivers and lakes. Wilderness System Tarpon series are good too. Depends a lot on where you live for what you can find used.
Avoid cheaply constructed wide heavy SOTs bought at big box stores for < $500 new. Mostly junk.