#1 My insecticide spray bottle with failed o-ring seal... No obvious specific replacement parts available, and what o-rings I did find that looked close were a major fraction of a new sprayer cost. The upside was that the new version sprayer had better features.
#2 Too cheap to be good electric toothbrush. Back at least 6 months ago I was looking for replacement for my old and tired electric toothbrush, I had fixed at least once (inside was corrupted by smutz). I saw a crazy cheap electric brush for the magic price of <$5. I bought it just to see what they could sell that cheap.

I'm sure this list will grow longer as we factor shipping cost into repairs. Some merchants will just send you a new product without getting the old one back. I have shipped some faulty stuff back not expecting a replacement because I was angry.
JR
PS: another cheap kitchen tool with limited service life was my manual can openers. I went through a number of them with half life measured in single digit years, before finally buying a decent electric can opener that seems more robust. I found this one model where the cutting head can be easily removed and washed inside the dishwasher, because that is a well known repository for all kinds of well fed undesirable biologic colonizations to transfer and contaminate food.