Javascript Code to Change Text Based on String in Page

Hello! On this page... [login to view URL] ...there's an area that says "Three Monthly Payments of $99" What's need is that when a coupon is applied that a snippet of javascript will change that $99 to $69.30 (try using this coupon as an example: SAVE30 ... and you can see what I mean) I was thinking maybe the script could search for the presence of the code SAVE30 ... if it was present in the page then display $69.30, if it wasn't present display $99 Hope that all makes sense. Sadly, for security reason I can't give you access to the page so I will need to add the script myself (it's in our cart system with credit card info etc. Thanks!