Ray,
Hi. Your explained your needs well enough but I will still reviewing what resources would be the best fit. I wished Dynamic Forms had the ability for you to enter a number such as '10' and a set number of the same fields would appear. We have reviewed the best way to add this and implement this down the road but we are still working on the design. What we might use that would fit most general circumstances is a grid where you can add items with a + / add in the footer and as you add items you can edit/delete them from the grid as well. So you could have a datagrid of 'Dependents' with columns for First name, lastname, boy/girl and you would able to add as many as you would like. There are a number of other scenarios we are looking at though but these would all be in future implementations.
What we have had clients do is a few different work arounds...
1. Have an initial form ask the user how many children they have, and then direct them to a different Dynamic Forms 2nd page (using the redirect event and base the event on field response from the user) so if they chose '1' redirect them to Page ABC and if they chose '2' redirect them to XYZ etc... You can pass along initial criteria on page 1 to page 2 such as we demonstrate 10 on the Dynamic Forms demonstrations page which covers multi page forms.
2. Use question events, you can setup many fields such as Child2, Child3, Child4, Child5 etc... For each field choose under advanced field settings to 'Initially hide field until forced visible by question event'. Using this feature you can have the user choose from a dropdownlist and based on their selection you can 'un-hide' those fields. So if they choose 2 it will show them 2 fields, if they choose 3 it will show them 3 etc... The advantage here is that its a single page.
In either of these cases the downside is that you do have a limited number, so you might have to go a route of '5 kids or more' and if someone has 15 they are in trouble
As far as calculations and price differences.... If you go with Option 1 you can simply setup the payment for to be set to a different price. This could be a static variable. If you go with Option 2 you will need to setup client side events that can offer a percentage discount or price difference based on the number selected. There are a few examples of this on Beta Springs but basically within the calculation to determine the price you would have a few if statements to determine what the full price should be. This is common/similar with implementations where you want users to be able to enter a 'Promo' or 'Coupon Code' within the form and for the price to change.
-Chad