It does not appear that Positive is a pro skating brand. Some brands of skateboard decks include Zero, Birdhouse, Blitz, Blind, Powell, and Element.
If you buy a pro board like in zumiez or any other skateshops boards would cost between $100 or $140 it depends what you whant on your skateboard and what brand of skateboard
Yes, Pig is a brand of skateboard.
Street grind is practically a bad brand. I suggest you to buy Hercules skateboard
Girl is the best deck brand out there.