I sold ~$1800 of clothing & virtual items this year – how will this work?

All money was received through CashApp exclusively. My CashApp is set up as a personal account, not a business account.

 

Any clothing items were shipped out of state (IN, IL, OR, WI, GA, FL, MN, RI, TN, CA, NC, CT, and IA.) and I have receipts from the post office. It's not a business & is not set up as such, I just sell clothing I no longer want and digital art, often at a profit for both. 
Any digital art was sent to the buyer without recording their state. 

 

I've been having my full-time (unrelated) employer take out an extra $50 per paycheck for taxes for Federal, and $10 per paycheck for State (MN) all through this year. I get paid bi-monthly, so the extra withholding should definitely cover my taxes.

My questions are: 

  1. Do the states I've shipped to matter? I'm not planning to claim the shipping cost as a business expense since my side gig is not set up as a business. If they do matter, what about the digital art purchases? What do I do for those? 
  2. Is there anything I should be doing differently going into next year, assuming I continue selling old clothes & digital art? 

Thank you!

(Edits: I inaccurately described this as a hobby originally, but for tax purposes it wouldn't qualify since most items I've sold were at a profit.)