The Dynamic Dropdowns works with Recordsets that you craft. So long as your data relates you can use recordsets that join multiple tables, but you will be limited to using a single recordset per list so make sure you craft the recordset to include all of the records that you need to filter through.
As for making the child menu hidden until a choice has been made the easiest way to do this would be to set the child list display to none, then update the onchange event of the parent list to set the display differently like inline or block. This is a very minimal amount of coding to get this effect.
The Dynamic Dropdowns is filtering recordsets based on your selections, so if you would like a quote to be returned after making the selections you need to make sure that you have a price for each possible choice and that it is in a table that relates to the last child list you are selecting from. When you filter down to this last part you can have it populate a list with the price.