Years ago, I bought a face cleaning tool for my daughter. It was supposed to "gently" suction her pores and help clean them. ha, ha! The only thing it did was left her looking like she had hickies all over her cheeks and nose. It was awful. Luckily, the marks faded in just a ouple days.
I once bought a small candle to stick in my pumpkin for Halloween. I stupidly figured a candle is a candle and just grabbed one off the shelf that resembled a small jar from the Yankee Candle store. I put it in the pumpkin and lit it and my house was filled with this thick blackish smoke and the next thing I knew the candle was on fire (I know how weird that sounds) but the container holding the candle was was on fire and it looked like the pumpkin was about to catch fire too. I managed to get the flame out and threw it all out. No more dollar store candles!
I have to say that most things I've bought at the dollar store have been decent quality but the one thing that wasn't was an umbrella. It was raining as I was leaving the store, and when I popped it open the thing broke in the parking lot! Really cheap.
I had a couple of stinkers lately. I tried buying some of the off brand body soaps at Deals, and when I went to use them, they practically poured out of the bottle like water instead of squirting out like a gel. Not to mention they would barely lather up, had practically no scent, and didn't clean well at all. Another lousy item I got there were some multi-colored tortilla strips for topping salads. When I opened the bag, they were all stale. The got to the point where they were no longer crispy, but kind of chewy with a rancid oil taste.
Amazingly, there are a lot of good items at the Dollar Store that people can pick up for only a dollar each but I personally think the worst item I have ever purchased would have to be a pack of pens that ran out of ink the second day. I was so ready to use them and thought they would last me a while but after a day they wouldn't work and then some just wouldn't work at all so I wasted a couple Dollars for those pens. I have to say, overall, Dollar Tree is a wonderful place to shop although everything won't be perfect when you buy it, its still worth the purchase. Paying a dollar each for each item isn't bad when considering stores with competition such as Kroger, Food Lion, Harris Teeter and etc.
The worst I probably bought from a dollar store was probably this really crappy USB vacuum, I guess it is my own fault for buying a thing that looked obviously cheap, but I was going to use it to clean up the crumbs stuck in my keyboard!
I bought a bag of chips from the dollar store once because I had a huge craving. I was expecting to be able to find a small branded bag, since those are usually $1, but all they had was large ones so I decided to try it out... but they tasted like dust.
I would have to say that the worst thing that I ever bought at a dollar store would be a cell phone charger. My phone charger went out and I had no choice to go to the nearest dollar store because my phone was almost dead. I live about 45 minutes from the nearest Walmart and I wasn't going to risk trying to go there and with my phone almost dead. I have a problem traveling without my phone because you never know what could happen. Long story short, I bought the charger and when I got home and plugged my phone up, the charger started smoking. Worst charger ever and a waste of money. I was to mad, not because I spent ten dollars on that raggedy charger, but I had to end up going to Walmart anyways without my phone to purchase a new one.
Off brand pastries and pop tarts tasted like sugar and cardboard. Lotion was totally ineffective, another lotion that stunk to high heaven. Maxi pads that made noise when I walked (so embarrassing), all purpose cleaner that didn't do any good. Laundry detergent that did not get clothes clean even when I used twice the amount they said to use, shampoo that felt like liquid hand soap and made my hair impossible to brush till did a vinegar rinse and rewashed.
My worst experience would have to be buying any kind of toy at the Dollar Store. I usually shop with one of my young boys and they always want something small from there. It's usually a toy! I have purchased toys over and over and we don't even make it home without it breaking. The kids are then so sad and want me to return it. ugghh. I wish they would just eliminate a lot of their toy section and maybe only carry 20 or so toys that will actually last a little longer than a few hours.