If you purchase items for resell and received a 1099k from selling those items where do you report the items initial cost?

@polestol  assuming that your business is a sole proprietor one , you report the 1099-K, the cost of Goods etc. all on Schedule-C.  Note that your net income is subject to SECA Taxes -- Schedule-SE  (  equivalent to FICA of wage earners but at the full 15.3% ).

Are you filing Schedule C for the business? 

Do you have inventory? 

I purchased TurboTax premium following the prompts on schedule C 1099K this is my first year reselling so I had no past inventory and 25K in inventory purchase this year Trying to figure out where I claim that expense

@polestol  if this your first year, then as of Jan 1 your inventory was zero, then as of 12/31/2025 your residual inventory was say $XXX.  You bought  Inventory  $YYY.  Thus  your COGS should be  $YYY LESS  $XXX.    TurboTax will compute COGS from your entries.

Does this make sense ?

Got it thank you 👍