electrical items unless they have the UL label ( Underwriters Laboratory safety inspection label )
Love dollar stores. There are man nay sayers out there that have lists of what is "supposedly" not a deal or smart choice, but I think it is a matter of personal opinion and need. One of my personal mantras for certain items like craft supplies, is "start at the dollar store and work my way up." For instance, I stopped in on one of mine last week that carries fresh produce. They had outstanding cauliflower. Yes the heads are slightly smaller than grocery stores, but at 99 cents a head v. $1.99 per pound, the dollar store wins. I bought 4, now thinking I should have purchased 6. My go to for greeting cards as Dollar tree has 50 cent cards as well as $1 cards. Drug store, grocery stores charge much much more. I am too frugal to spend $5 or more just for a greeting card that most people just toss. (I don't, mine all get recycled into crafts eventually.) So use your best judgment and go from there.
Here in the UK Poundland has just started selling engagement rings!