Don't worry, they'll find a way. Spending money is ridiculously easy, making money, that's hard.

I made a rough estimate what instagram spend on hosting just before FB bought them, and I wouldn't be surprised if that was a few 100K/month. At this scale, and especially AWS, this isn't cheap. If snapchat supposedly does 50 mln imgs/day, their hosting also won't be free.

Also, if they could raise this at a nice valuation, it gives them a nice runway.