Hi, if I buy add on packs for the express version and later decide to buy the full Pr version do I get any discounts? Or is there any upgrade path?
You do indeed get a discounted upgrade to Pro from Express with Add-ons. How much varies depending on which pack it is, obviously.
As an example right now (this may be subject to change in future), the Sci-Fi Adventure Pack is $25. If you upgrade to Pro with just this pack on your Express license, you get a little over $12 off - so about half your money back.