How do I get Started with Dynamic Web Pages?

I am presently following Janine Warner's Dreamweaver CS3  video series.  I noted that the Advanced part of this tutorial series focuses on Dynamic Web Pages, but only uses Cold Fusion.  From what I can gather, CF costs around $1000, while PHP is free!  My question is really this: in going from static to dynamic web design I'M A COMPLETE NEWBIE, so what do I need?   I am doing some planning here -- I know it won't happen overnight.

(BTW:  I was surprised to discover that CF is NOT included in my CS3 Master Collection).  It might appear then that support for PHP is better than for CF?

Apparently, I need a server -- well, OK I have PCs to spare.  Fast internet, I also have: Comcast standard -- 12MP

Now, I think I also need Apache -- which apparently runs on the server and does something.

So then I DL PHP, figure out how it works, and it will integrate with DW CS3 in some way.

Now, what have I missed?  Is there some really basic, first-time-with-using-a-server place or tut I should go to or read?  Before you ask: No, I'm doing all this myself on a shoestring budget.

Are there expensive hosting fees for dynamic web sites or other items I will run into?  Can I just use a PC over my Comcast cable as the server run from my home?  (Really high traffic is not anticipated)

All recommendations appreciated, thanks.

Thom