Whelks are truly a treasure and they're not always easy to find. Sometimes when you're walking along the surf, you'll see a tiny pointed tip. Dig that up and you could find treasure - a whelk! Mostly, though, you'll see whelks along the beach or in the shallow water among the common shells. There is a "no live shell" restriction. I know it can be disappointing to toss a really pretty whelk back to sea if there's an occupant, but it'll give you a reason to come back another time.
I've been in love with having sand between my toes since I was a teenager taking the ferry across the bay to arrive at Presque Isle State Park (aka The Peninsula) in Erie, PA.