If a taxpayer receives income for an activity that they don’t carry out to make a profit, the expenses they pay for the activity are miscellaneous itemized deductions and can no longer be deducted. The taxpayer must still report the income they receive on Schedule 1, Form 1040, line 21.
In view of the above from the IRS, I don’t understand how the OP can deduct the expense of buying the cards from income assuming that the activity is a hobby.
