PTCLucky.click is a website where users can click on advertisements and have to look at them for a certain time. The user then receives a sum of money for this. A PTC website acts as an intermediary between the visitor of the site, or the consumer, and the advertiser. The advertiser pays to be allowed to advertise on the PTC website, part of this amount goes to the consumer as soon as he views the advertisement.
Yes, they are legal to make money. You are earning for your hard work, and all the PTC sites are approved and already paid huge money to their members. You can join any PTC site for free you can make money legally.
It will be better if you join premium membership because of the additional benefits of instant payments and more surveys.