Yeah no I have to agree with you on this one. Every company is going to raise prices at one point or another - it might be inflation, it might be profit-chasing, padding for an IPO - whatever.

Just because a startup might raise prices in the future shouldn't stop you from using their products - with a caveat, that is, how easy it is to shift to another operator. I haven't used fly.io personally, so I don't know about that - could you elaborate on shifting to another provider just in case?