It doesn't make much sense in case of a toaster, but if you bought a pen (or socks, SSDs, lightbulbs, etc.), you may buy some more after you tried it and liked it, or maybe you will try another brand.
I guess it's more like a continuum than two discrete categories. On one end of the spectrum there's a family house, on the other, there's toilet paper. That's why they repeat ads even for a toaster.
I suppose I'm wrong because it appears not to exist. But, I can't get past the idea that there's just a lot of things very few people have more than one of. Many of them being big ticket items too, where the cost (or opportunity cost) for a wasted low-conversion-rate ad is high. Like bbq grills, most types of power tools, air compressors, automotive battery chargers, refrigerators, washer/dryer, dishwasher, lawnmowers, etc. And many of those have obvious companion items that would be a better use of the ad space than trying to sell someone a second bbq grill, for example.
