eBay $25 supplies credit promotion 6/08 till 6/30/2020
I received an email on one of my eBay counts offering me a $25 credit on eBay shipping supplies. The coupon code is "thankstoyou"
On a whim, I tried it on my other eBay account and it worked there as well even though I hadn't gotten the email on that account.
I don't know if it will work for you, but it's worth a try. There's no minimum purchase, so you can get some free stuff if it works.