Just bought a 2013 v. Is it worth it to buy the platinum extended warranty, and if so, what should it cost, and where would be the best (reputable , non-scam) pace to get it?
No, its not worth it. Your standard warranty provides extended coverage for power train and hybrid system, so the "extended warranty" only covers the other stuff. Read about it before making a decision: Toyota 2013 Prius V Warranty and Maintenance Guide The odds are overwhelmingly against you ever needing this.
Do you play a lottery that pays off around 30% to its players? Then buy the warranty. (Consumer Reports figures) Just like the lottery or casino, a very small number will win, a few break even but the vast majority must lose to fund the selling expenses and the few payoffs. You'll hear from those who win, those who lose aren't as vocal. (I say this as someone who has made money at the casinos (who pay ~90% generally) over a lifetime but who hasn't found extended warranties for things I can afford to repair ever worthwhile. I insure my house, against liability, my car against the 5 car accident involving the expensive cars (but with high deductables), against health expenses, etc. Not the little stuff (phone, tablet, computer, cameras, appliances, yard equipment, HVAC, etc) because overhead and profits make those bad deals over a lifetime. If the little stuff fails, I can afford to buy a new item of my choice with the money I saved just that year by not buying all those warranties on everything. I'm 70.) You may be in the small percentage who have a different experience. Or your risk tollerance may make it such that buying the warranty enables you to sleep better at night. We are all different. But at least you now know the odds.
They call those plans platinum for a reason...the dealer makes a platinum sized profit selling them. Save your money and forget about it Look at CR and how reliable a Prius is...why pay thousands more for nominal benefit.