Also tell me your experiences with business subjects, do they help at all?
Both Business Studies and Economics provide students with a foundation of knowledge that can be useful beyond the HSC, depending on your study intentions.
The Business Studies Preliminary course introduces business and the business world. It also explores basic business concepts (namely business management and business planning) and functions. The HSC course covers the different aspects of four business functions. They are operations, marketing, finance and human resources. The HSC course explores the role, influences, processes and strategies of each of these functions, with the human resources topic featuring an additional effectiveness component. The HSC course also involves learning and applying real-life business case studies to assessment tasks and exams (including the HSC exam).
While Business Studies is not treated as a prerequisite or assumed knowledge for any degree, taking it would be a good idea if you intend to study a Bachelor of Business/Commerce (or similar degree) as the knowledge gained from studying this subject can allow you to have a more comfortable start to university, where concepts from the HSC course are likely to be revisited.
As you can see, Business Studies covers multiple areas of business at a slight level of depth. On the other hand, Economics covers only one area of business, but in more depth.
The Economics Preliminary course (similar to Business Studies) introduces the field of economics and explores concepts such as consumers and markets. The HSC course covers the global economy and Australia's place in it, while also exploring economic issues as well as economic policies and management.
While Economics is also not treated as a prerequisite or assumed knowledge for any degree, taking it would be a good idea if you wish to study a Bachelor of Business/Commerce, a Bachelor of Economics or a Bachelor of Actuarial Studies (or similar degree) for the same aforementioned reason.
A fun fact is that the Business Studies HSC course includes a slight economics component within the finance topic, notably the economic outlook and exchange rates.
I hope this helps!