since I didn't see any other alternative, the digital guage seems to have worked.

First, drag all of the related form components onto an AJAX DynamicUpdatePanel component.  This would presumably include your grid components, as well as the ASCII Merge Label which shows the Estimated Cost.  Next, set the grids to "Post Value On Form Change" on the Functionality tab of each grid components' settings.  (Note this checkbox for Post Value on Form Change will only be available if the grid is set to allow "Select Items".)  By enabling Post Value on Form Change, every time the grid selection changes, the part of the form which is in the AJAX panel will "update", which then allows you to display a dynamically updated value within the AJAX panel via an ASCII Merge Label.

Write back if that doesn't make sense or if you run into any issues with this method...

Hi Dalceon,

How did you highlight the row with a different color? I looked at the On Click event under the Custom Events but it just takes you to the Advanced Text Editor.

If your "Grid Mode" is set to "Select Items", then the row highlighting should be automatic.  There are several grid style presets to choose from on the Response tab, but they all seem to have this characteristic. 

If your Grid Mode is not set to Select Items, though, then your grid isn't geared towards having users select rows, and therefore the highlighting doesn't happen...e.g. if you're set to Editing Items, you want users to think about clicking into individual cells, not whole rows, and so it would be distracting to highlight the whole row.

Thanks Chris, I never noticed it because I've only been using the Editing Items and Readonly options in the Grid Mode.

Unless I'm missing something the Ascii Merge Label doesn't offer a dynamic model as its source to do the calculation. the guage does.

Sorry, I was focusing more on the dynamic updating part of it, and had overlooked the fact that you're trying to do some math directly on the form.  So unless you're putting a button on the form which will both force the update and leave the form (and come back), your best bet would be a form-based calculation component, like the digital gauge.