Wrapping food in plastic is never a good idea, especially when it comes to cheap plastic. The producers use BPA to soften the plastic, and our bodies view it as a hormone. BPA substitutes are not harmful, but they are expensive and hard to produce. That’s why small manufacturers have to rely on BPA to make their products.
It is slowly released into the contents of the bag, and it can harm your health in the long run. If you insist on buying them, the dollar store items are not really the best way to go because they are incredibly thin and the seals rarely work.