Displaying selection based attributes in a table?

Question

I have a table column, where data should be entered through a dropbox. Depending on selection an additional value should be asked.

What is the best way to display this value in the table?

Answer 1

I'd leave some space out for it:

^{download bmml source – Wireframes created with Balsamiq Mockups}

(Balsamiq didn't want to catch the € sign for some reasons...)

This way the size of the grid doesn't change, and even without an additional label it's obvious what's the input is for (esp. if you add a currency sign at the end)