Definitely not scam. It works well if under "normal" scenario, i.e you complete the assignment and they'll pay you. Under some "special" case like the site is closed and etc, you'll have to after the payment and beg like a begger for your payment. Not a very good experience. Payment wise it will be high and low but averagely around RM30 (net earn). If you want to join them, you should really consider whether you want to spend the time to beg and after your payment sometimes.