Don't forget that besides simply reusing a used pipe cleaner or washing it to reuse, you can also trim the dirty end with a wire cutter and use it until it's too short for any purpose.
Yup, you can thank me later.
On a more serious note, it's not just the cost of the cleaner. It may be just a few pennies each, but it's a lot more to all of us collectively. We all have to pay for garbage haulers and landfills, polluted ground water, etc.
The cost is also more than economic. About 10 years ago I was in the Malaysian state of Sabah, on the island of Borneo, on a wooden boat travelling to a nearby island. This was near where the first Survivor series was filmed and it had taken me more than a whole day to fly there from the States, with plane changes. It felt so good to be there and it was stunningly beautiful. The sky was blue and the water bluer. It was paradise. But floating in the water in front of the boat as it chugged along was an empty plastic water bottle, the type you can buy by the dozens for less than a buck each at Walmart. It was goddam the ugliest thing in the world there. I've hated water in plastic bottles ever since. They are unnecessary. It didn't cost the idiot who threw it away a damn penny but it sure cost the rest of us the price of paradise.