Looking for online card sellers

I'm looking for reputable vendors or sites where I can get authentic pokemon packs that aren't resealed as I have seen on some pokemon cards at good pricea. I got into pokemon years ago but with all the awesome looking cards I've seen I can't help but just acquired some authentic packets online at a good price. I've gotten some of Amazon and the packets were full of duplicates and energies so I rather try my luck with packets. Any indications would help me get back into the card game, thanks!