I say "No thank you, go on to your next call" and hang up.
I feel sorry for these folks, some times you can hear their kids fussing in the background, or get someone obviously having a difficult time learning how to read their script. You know these are just everyday folks trying to earn a few extra dollars for whatever reason, needing to do something to work from home. They're not the Big Bad Corporate Execs manufacturing or marketing the product, just the poorly-paid drones trying to get by.
Some people complain "Why do they always call at dinner time?" but just think, these callers are missing their own dinner time having to try & make a few sales by calling you. If you don't want your dinner time interrupted by the phone, just turn the ringer off while you're at the table.
But there's no need to be rude or harsh or mean to the people making the sales calls. They must have an awfully tough job. Just say "No thank you" and hang up.