Steve without wishing to be rude maybe you should have asked that before you purchased it.
OK Why go pro, simple answer is you can now make all the
coding changes you want (using the
coding on this site and the
OBD11 Forum) and check out the link in my signature for other links. If you don't go pro you are limited to what you can do and have to pay for everything.
If you read this
http://forum.obdeleven.com/thread/1935/credit-system it will explain about the credit system but you only need credits if you are using apps. You get 6 free credits a day but have to watch adverts now that you are forced to watch all the way through.
Be warned the facelift and pre-facelift cars have different
coding for some parts of the car due to VW Upgrading the setup so make sure you look for the correct car.
Last point to
help you save yourself (and we have all done it) from errors. Backup all your control units before you start doing any changes