What is the oldest Mac Computer I can get that can have internet and play DVDs?

I'm not really much on computers, so that is why I'm looking for something cheap, but still can have internet and play DVDs, and also if it can run videos as well.
( just for extra, can also connect with an Ipod/iphone)

So you want something cheap but you want to get a Mac, What sense does that make?
Go buy a cheap $100 laptop off Craigslist and go get a USB DVD drive

Personally I would not go further back than an iMac or MacBook made in Late-2006, prior to that and they will be unable to run modern internet video sites in a good quality. This is also the last model that can run the version of MacOS X that is required by the newer iPhone/iPods (10.6.8 Snow Leopard). Just remember these computers are going on 7 years old now and will not be fast at anything. On eBay they go for about $200-$600 depending on the model and configuration.