If you send it via standard postage, it will rarely get returned back to you if the address/recipient is incorrect.

Section 8 recipients lose their voucher eligibility if they get evicted.

I don't like strange unsolicited texts either but I bet the recipients don't like cold calls much more.

Apparently, manually sending messages using your cellphone is legal, but my take is you can basically only send one per recipient. 

Auto dialers, without consent of the recipient, is illegal.

However you  have to set a clear criteria and just paste it to all recipients so that you don't waste time entertaining them as many people would just click "Is this available" and will start spamming your messenger notification@Carlos Valencia @Albert Bui

Many section 8 recipients have a lot of kids and sometimes the number of people exceeds the number of bedrooms so check your municipality for the limitations on that.

Issuing more than one would be confusing for the recipient and the IRS and could lead to audits.

Once you have the gift card take it to the bank and use the value of the gift card to purchase a money order naming yourself as the recipient, then deposit that money order into your bank account. 

If you think it stops with the recipient of the voucher you are sadly mistaken.