You can deduct out pocket costs in provided service to a charity, but any items you pay for must become the property of the charity or be used up in providing service to the charity. For example, you can deduct the value of a computer and printer if you donated it to the charity and they took ownership, but you can't deduct for the use of your computer and printer in printing a newsletter. You can deduct the cost of paper and postage, if you have receipts. You can't deduct for your own newspaper, since it is yours and not the charity.
Also note, the charity could reimburse you tax-free for any costs you pay related to your service, and you could then donate part or all of that money back to them.
Finally, if audited you would likely need a letter acknowledging that you provided these services or paid for these costs on behalf of the charity. The letter does not have to attest to a specific dollar value, as you will do that separately with receipts or other proof. But the IRS can ask you to prove that the paper and postage were actually used for the charity and not something else.
