Here is something that will work..at least with IE. The function is attatched to the onChange event for the dropdown menu. I didn't write any onload events or anything so this thing will start working once you change the dropdown menu for the first time. You can easilly modify it to your liking:
one other thing, i noticed that you had some quotes in your values. I don't know what you're doing but one possible work around is using ". It works in the alert boxes or you could write a little regEx to put them in:
<option value="19.95" otherVal="24" x 36 - Photo Glossy Paper">24" x 36" - Photo Glossy Paper</option>
<option value="24.95" otherVal="24" x 36 - Satin Finish Paper">24" x 36" - Satin Finish Paper</option>
update: this bulletin board is rendering my HTML encoded quotation marks. my work around is to put the HTML encoded version of " next to your numbers. follow?