Case by case basis I guess. Usually they just amuse me.
Just today I got a simple “7.00…?” for an item I have listed at about 15.00 including shipping, and have sold a couple dozen at that price in the last 6 Months or so. I just ignore.
Anybody ever get “Will you take blank dollars for it…I can PayPal you right now” on an auction item that already has bids well above what they are offering? This has happened more times then you might think and it’s not because they sent their offer before the bids got put in.