The easiest way is to get a test account for Authorize.NET, thats what I use for storedemo.mojoportal.com
if I add an offer and associate with 3 products, will a completed order add the 3 products to the orderofferproducts table?
Yes, the idea is that offers may change over time but we must always have an accurate reflection of what products were in the offer at the time of the order.
Hope it helps,
Joe