laptop question(apple) and ebay question

So I was thinking about getting a laptop. I think that I will end up getting a powerbook off of ebay. It will save me about 230 dollars, which is alot to me.
BUT
If I got one like this would I have to use the airport express card in it or could I just use one of the older airport cards?
How much faster are the new intel macbooks? Would I really notice a difference just for basic stuff like email and internet?

Also would you recommend going off ebay or what would you say about that?

Thanks in Advance.

Item #13770. Includes computer, battery, AC adapter and power cord (no Airport Card). Does not include software CD’s or manuals. OS X v10.4 Installed.

does it come with an airport card at all?

No, but it says on there that it is ready for an airport express. So I was wondering if you needed it or not.
I will talk to my stepdad about it tommorrow, but It would be good to get some info from unicyclists that may know some stuff about it.

You only need the wireless card if you want to connect to the Internet (or another network) wirelessly. If you don’t buy an airport express card, you can always use an ethernet cable to plug into a broadband router.

P-p-p-powerbook.com will give you an insight into buying laptops on ebay.

I have already seen the P-p-p-powerbook, and I am going to buy it from a reliable company I saw in my macaddict magazine.