Is it possible to get the value of a line item in a Workflow? I need to grab the value of a custom column in the line item, to use it in a new line item.

This might be possible....but your criteria would need to be pretty specific and based on a field in the line. For example if you want the value in ColumnA then you would need to find another specific value for that line like lets say "Amount = $1" or Item = ABC. But you couldn't say copy line 1 into line 2 or anything like that. Does that make sense?