A static IP is not the only way to do this - indeed if I were consulting on this project I would not place the primary hosting on your site. However working out how to connect to the internet is not the first step in a project like this.
If you don't even know how to begin doing this, I would VERY strongly recommend that you get some help.
As soon as you connect to the internet you are a target for other people to attack. If you're running a server then you're not only advertising the fact that you are available for attack, you are exposing services which may be used to leverage an attack.
dBase files are not the right medium for storing data on a multi-user system.
I'm cautious about pointing out some of the things you should be considering in case you interpret this as providing you with all the information you need - sorry, but you're a very long way from being able to build this system.
Actually building systems is one of the best ways to learn - and I'm all in favour of that. You might consider investing your effort in building some basic tools for interacting with the data using PHP - and defer exposing your systems on the internet until you've acquired a LOT of knowledge.