Its entirely worth it and its not even that expensive. Also having the non trial version will help you a ton. Being limited to only 100 events and not being able to create subfolders for layouts and things is harrrsshhhh.
My suggestion is just play around the free version, learn, get used to it, try making a few small projects. Heck even start your bigger project but pre-develop it in a few projects (cause of the event limit).
Then when you are READY to launch something, upgrade before you monetize and you should be good, and that cheap investment should get returned quickly ;D