penguins_dont_fly is a Volunteer Community Mentor
As I've mentioned in the other thread, I suggest that you consult an accountant or other tax professional. By the way, their fees are deductible as business expenses. 
https://fitsmallbusiness.com/schedule-c-profit-and-loss-form-1040/
4. Complete 1040 Schedule C Part II – Expenses Section
Below you will find a brief description of what information you need to report in the Expenses section of 1040 Schedule C and some tips on how to do so.
Line 8: Advertising – Include money spent to advertise your business such as flyers, business cards, or an ad purchased on Facebook.
Line 9: Car and truck expenses – You have the option to deduct the actual expenses of using your vehicle for business or taking a standard mileage deduction. Check out our guide to see which method will give you the largest deduction.
Line 10: Commissions and Fees – Include any commission payments or referral fees made to sales reps or others.
Line 11: Contract Labor – Payments made to independent contractors for services provided to your business belong here. Do not include any wages paid to employees on this line.
Line 12: Depletion – Depletion is similar to a depreciation expense but it is to account for a significant reduction of a natural resource. This is typically used by mining, timber and petroleum businesses.
Line 13: Depreciation and Section 179 – Include the annual deduction allowed to recover the cost of business equipment or investment property used in your business that has a useful life beyond the tax year. To learn more about how to calculate this deduction, check out our guide on Section 179 deduction.
Line 14: Employee benefit programs – Deduct contributions you made to employee benefit programs like health insurance plans and life insurance.
Line 15: Insurance (other than health which belongs on Line 14) – Deduct premiums paid for business insurance such as liability insurance.
Line 16a: Mortgage Interest – Deduct any interest that you paid to a bank or financial institution for a mortgage that you have on a building you use solely for your business, such as a warehouse. You should receive a Form 1098 for the total interest that you paid.
Line 16b: Interest (other) – Deduct interest payments that you made but did not receive a Form 1098 for.
Line 17: Legal and professional services – Deduct any fees paid to accountants such as tax prep fees or any fees paid to an attorney who represented your business.
Line 18: Office expense – Deduct office supplies and postage expenses.
Line 19: Pension and profit-sharing plans – Deduct any contributions that you made for the benefit of your employees to a pension or profit-sharing plan.
Line 20a: Rent or lease vehicles – Deduct payments made to rent or lease vehicles, machinery or equipment for business. If you leased a vehicle for more than 30 days, refer to the IRS Publication for additional instructions.
Line 20b: Rent or lease other business property – Enter the amount you paid to rent or lease property such as office space.
Line 21: Repairs and maintenance – Deduct minor repairs and maintenance that does not add to the property value. For example, paying a plumber to repair a toilet or to unclog a sink would go in here.
Line 22: Supplies – Deduct the cost of materials and supplies used in your business. Some examples are books or small tools and equipment.
Line 23: Taxes and licenses – You can deduct state and local sales taxes and licenses. If you collected the tax from the buyer, you must also include the amount collected in the gross receipts (line 1). You are also able to deduct real estate and personal property taxes on business assets, licenses and fees for your trade or business (i.e. business license), and social security and Medicare taxes paid on behalf of your employees.
Line 24a: Travel, meals, and entertainment – Deduct expenses for lodging, transportation and meals while traveling away from home on business. Learn more here about deducting travel expenses.
Line 24b: Deductible meals and entertainment – You can deduct up to 50% of eligible meals and entertainment expenses. Learn more here about deducting entertainment expenses.
Line 25: Utilities – You can deduct telephone expense, water, electricity and any other utility expenses you paid for your business.
Line 26: Wages – Enter total salary and wages paid to employees for the tax year. Do not include amounts paid to yourself.
Line 27a: Other expenses – List any business expenses that you did not report on lines 8-30. Some examples of expenses that belong here are bank service charges, computer supplies/equipment, dues and subscriptions for trade magazines, and training and conference registration fees.
Line 28: Total expenses – Add lines 8 thru 27a
Line 29: Tentative profit or (loss) – Subtract line 28 from Line 7 (Gross income)
Line 30: Expenses for business use of home – You may be eligible to deduct expenses for the business use of your home. This is called the home office deduction, and you can learn more about it here.
Line 31: Net profit or (loss) – Subtract Line 30 from Line 29.
Line 32: If Line 31 is a net (loss), you need to check one of the following boxes:
- 32a: All investment is at risk – Select this option if you have a business loss and all of the amounts you have invested are at risk, meaning there is no protection against the loss such as insurance.
- 32b: Some investment is not at risk – Select this option if you have a business loss but not all of your investment is at risk because you have some sort of security or protection against the loss. In general, the at-risk rules will limit the amount of loss up to the total amount that you have to lose “at risk.” Refer to the at risk rules listed in this guide for additional details.
(Almost) anything that is DIRECTLY and EXPRESSLY used by your business is deductible.
Some basics ...
Office Supplies ... paper, ink, pens, pencils, staples, etc
Packing Supplies ... boxes, bubble wrap, envelopes, labels, packing tape, styrofoam, tissue, etc.
Storage Supplies ... totes, shelving, etc.
Office Equipment ... did you buy a new computer, printer or scale this year that is used exclusively for your eBay business?
Do you pay for cloud storage of your documents and or pictures?
Take a look at everything that you use everyday in your business ...
With your home office deduction, ask your accountant about how much of a percentage of your household phone (landline and cell), internet and utility bills can be deducted.
