We have known for a long time that ARIN would be depleting their IPv4 address pool sometime this year. It happened yesterday Sept 24, 2015. So what does that really mean? Unlike some of the other RIRs around the world, ARIN chose to not have any excess reserved pool but to simply completely burn down what IPv4 address blocks they have left in inventory. This means that unlike other RIRs there is not "reserve" bucket at all to reach back into.
Honestly, while the event in very important we are still going to see IPv4 use for a long time. The reason why is that the majority of small and medium sized businesses still get their IPv4 address space from their local service provider. These ISPs still have IPv4 inventory left. I haven't seen any consolidated information about how much inventory major US providers have left but I can imagine at least several years worth. So, if a business needs IPv4 addresses they can still get them.
I do think to get them you will pay more money. Plan and simple economics come up. IPv4 is now a scarce commodity and the price per IPv4 address will only go up over time. This means that IPv6 addresses will become more common as they will be the cost effective option. Especially since that is the only way for the service providers to continue to grow and add customers. So for customers demanding IPv4 for any reason they will have to pay more and those that are willing to go IPv6 only will likely get the most cost effective service pricing.
The other impact is that a lot more folks are going to have to start getting comfortable with IPv6. How to manage it, use it and write applications that run on top of it. There is no way you can claim to be an early adopter of IPv6 at all now but you can certainly join the rapidly growing group of users who are learning and using IPv6. IPv6 is the future and the future is now!