I spent the last 10 years working for an eBay seller with better than 150,000 transactions in that time frame. While there is never a guarantee, particularly with live plants, there are some areas you can check to see if a seller is reliable overall.
black*ridge has been selling on eBay since March, 2000 and has 12K+ feedback at 100% positive. A good sign.
Of 676 items currently listed for sale, 180 are Iris. Which means the seller's feedback is a more solid indicator of integrity than might be the case with a seller that ONLY sells live plants.
Of 1,256 feedbacks received in the last 12 months, two were negatives. One related to a fabric, the other related to a citronella soap that didn't repel Texas mosquitoes
(I kid you not).
So, while it is always a buyer beware situation, in this case, the seller looks to be okay.
Hope this helps.