do you need static ip for a server?

Although there are workarounds, yes, as a rule of thumb you need a static ip in order to serve any type of web service.

It's possible with Dynamic DNS such as http://www.dyndns.com but not worth the hassle in my option. Static IP is the way to go.

You need to have atleast 1 static Ip in order to provide web hosting services..

I am going to take a guess here and guess you are thinking of hosting from behind a cable modem or a DSL line. If that is the case, I had experience with this in the late 90s in my parents basement. First off, if you can afford to pay extra for a static IP address, you are going to take a lot of stress out of your setup, and possibly cost, as I will get into in a second. If you want a TLD (top level domain like whatever.com) that domain will need to be pointed at an IP address. Every time that IP changes, it's gonna take 12-48 hours for your server to come back online. So you will either have to deal with that downtime, or pay for a dynamic dns service that supports TLDs. There are free dynamic dns services out there, but none I am aware of that do TLD.

If you do pony up for a IP, but not a Dynamic DNS, you are most likely going to run into dns problems. Most home ISPs (especially in the US) are going to block your IP from registering as DNS server. So you are going to have to have someone else do that (like zoneedit.com). It is even less likely they will allow you to provide RDNS for your IP(which there is no way to get around except ISP sweettalking). It is also worth pointing out that most of these activities probably break your TOS with your ISP.

But if all those issues sound fun, it's a great way to learn some stuff.