Usually the cost basis of something given to you would be whatever the cost basis was to the giver, eg what they paid for it. However, since you received the items from your dad upon his death, the cost basis of those items is the Fair Market Value exactly on his date of death, e.g. there was either a "step-up" (if worth more than what dad paid) or a "step-down" if worth less than what dad paid. You have basically proved the FMV by selling them on the open market within a reasonable period of time. You should owe nothing and may even get a deduction for whatever fees you paid Ebay and any other expenses of the sales.
