So you are saying it is illegal to buy plants on Ebay that are imported?
If I just need a small amount of plants it is more economical for me to buy on Ebay.
Yes, somewhatshocked is correct.
Importing plants from outside the United States is illegal without proper phytosanitary certification.
When you order plants from outside the country you become an 'importer' and are responsible for the shipment (not the seller). The vendor you mentioned does not provide phytosanitary certificates and tries to get around government regulations by labeling the shipment 'glassware' or anything but live plants. If it is caught by U.S. Customs and/or the USDA you will be contacted. My favorite story what when the feds showed up at a hobbyist's place of work because that is where the shipment was delivered.
If you do a search on this forum under phytosanitary certificate you will find multiple threads dealing with this issue.
If you want more information on the subject start a new thread, this thread deals with Oil-Dri.