Where do I list the FMV or cost of goods sold on Ebay? I received a 1099k from Ebay, have entered that in Sch C. Not a business. Just needed money during covid.

If this is not a business and you just sold used personal items on Ebay, then please be aware that if you sold these items at a loss (i.e. at a price which is lower than what you paid them for) then you have realized a loss. Losses on personal items are not tax deductible and you do not enter these sales on your tax return. In this case, just keep that form 1099-K in your tax records along with any proof you may have that the sales are sales of personal items at a loss.

Please read this TurboTax Help topic for more information.

I understand we will have a loss, but the 1099-k is for $20k. It was my understanding we are able to list the ebay fees, postage/shipping costs and list the items to balance out the $20k, since it was not actually for profit.

If you have a loss, the loss is not deductible as it was on personal items. You do not report the form 1099-K (even if it was for more than $20k).