For sure avoid all those cheap aftermarket props on Ebay and amazon. Only the best from Master Airscrew. Because we all know, DJI don't make their own props....they buy them from someone else, too.
Prices are creeping up but I think he's too far ahead of the game, maybe in a month or so. I think the word is getting out that S.Korea is the only "safe" place to buy your CC online at eBay, all the others you could have issues related to...