If your primary concern is safety, which it sounds like it is, then don't buy anything that doesn't have a legit UL cert and don't ever use a product except for the application it was intended. Done. Spend the money and don't worry about it.
If you are an engineer, then you can make your own informed decision if spending less money on a product with unknown quality is worth the added danger. If you can't make that decision yourself (with a high degree of confidence), you probably shouldn't be asking people on the internet if applying a roll of electrical tape will keep your house from burning down.