If you know a film has been illegally copied and is being sold as a knock-off, don't buy it. If your favourite designer brand is clearly not made by your favourite designer, stay away. Beyond these obvious counterfeit products, stay alert to other warning signs. If a medicine that you know normally requires a prescription is available online without any sort of script from a doctor, then it could harm your health, perhaps irreversibly. Remember - while these purchases may save you money in the short term, the longer-term losses are far more costly.