To legally import seeds (or plant parts - live or dead) you must have an import permit as well the plants (or parts) must be accompanied by phytosantiary certificate (i.e "clean bill of health" from the exporting country's agriculture dept.). Since Nepenthes are almost all Appendix 2 (N. khasiana and N. rajah are on App. 1) of the endangered species list of CITES (Conservation In Trade of Endangered Species). This documentation must accompany CITES protected plants (or animals) when shipped internationally. These documents state (officially) that the plant (or parts) are from artifically cultivated (not wild collected) plants.
There was an update to the importing of seeds due to "possible biological agents" being distributed on seeds a year or so ago. but I do not recall the exact details whether seed importing was to be halted or would just be watched more closely.
Actually, I'd pay up to $1 per seed so I think the current price is great, the risk however, is greater. I do not recall The Griffins exact thread but I'm sure he will pop in and recant the expensive details. I think the fine was $2500 and the plant was originally $20... And it was the SENDERs screw up, Griffin had the necessary import permit but the sender didn't have the phytosantiary or CITES paperwork (this paperwork is not generally free so unless they do a volume business you will usually have to pay extra for these documents) The sender also lied about the contents of the package on the outside of the box.
Importing can be a risky thing when you deal with a new company or a possible "smuggler", or rather, someone who doesn't know the laws. In this sense "smuggling" of cultivated plants is not smuggling on a sinister level, just ignorance of the laws. But as they say on the lawyer shows "ignorance of the law is no excuse" and saying you didn't know won't get you off. With no paperwork how do you prove that you grew it? The federal government takes this seriously.
For more information, read the book Orchid Fever by Eric Hansen for some very dreadful tales of the tactics used by the government to halt the international underground orchid trade (not exactly the same as Neps but are classed the same as "endangered flora"). Including raiding greenhouses in guerilla combat style with uzis and attack dogs as if they were busting a drug lab or mafia stronghold.
Just be careful when dealing with sellers outside the USA (or your home country wherever it is) CITES is an international treaty and is enforced in almost every nation. Actual nurseries who deal in plants are generally safe to order from as they are registered with their governments and know to send the apropriate documentation for the country they are exporting to.
Here is a link to some reading information on APHIS the department of the USDA who handles the import permits:
http://www.aphis.usda.gov/ppq/permits/plantproducts/index.html