Product for free when you buy

I will Product for free when you buy

buy 100 US and get free product Automatically in cart!

Can anyone help?

Most payment gateways requires a minimum $1.00 fee per transactions. The only way on achieving this would be for the customer to be advised that a free product would be involved after a certain mount of purchased products and once the checkout is completed and the order status not yet set as completed, it is possible to add a free product from the store afterwards and before the official order email confirmation gets sent to the customer when the order status is set as completed from the admin but must NOT be set as completed during checkout.

Another inconvenient matter is for guest levels that would purchase products. How would each checkout process be distinguished if we can't identify the account ?

I want to apply that when you buy a specific the amount!


Example:

Buy at $ 200 and $ 100 and get 1 free product!


Another example:

Buy Product No. 1 and No. 2 producer, and get the No. 3 free product!