There may be cheaper ones, try ebay too.

If what I told you to do to check your keyboard was too hard, let me try to make it simpler:

There is a link to Hiren's Boot CD down below in my Signature Pic. The Download link is on the webpage that comes up, down at the bottom. Download that, and stick a CD into your drive. Then right click on the downloaded file and tell it to "Burn to Disk". Its about 600 megabytes, so it's not too large.

Then stick the burned CD into your laptop and it will boot to it, you will see an entry that says "Mini XP" use the arrow keys to scroll down to that and just hit ENTER. If the laptop does not boot to the disk, then press F12 while it is starting, and you should get a list of Boot Options, choose the CD/DVD drive. Some HP computers use F1 or escape instead of F12.

You can test your spacebar with that, just open Notepad and try typing, see if the spacebar works.