Self employed

Thanks Vicent!

 

Since I am considered self-employed and need to file taxes quarterly, I'd like to ask a few follow-up questions. 

 

Questions:

1. What are considered expenses? I am thinking of "Cost of Goods", "Platform Charge", "Freight Charge", "Office supplies", "Software Subscription Fee", "Part of Utility Bill", and "Internet". Are any of them not eligible for expenses?

 

1-1. Am I allowed to claim part of the utility bill and internet as expenses? I will claim the home office and use one of the bedrooms exclusively for this business.

 

2. If my business net income (revenue - expenses) is negative, do I still need to file quarterly sales tax and self-employment tax?