I would personally only sell those items to the States if they're tracked. Based on where you are located, you should be able to use a cross-border shipper like Stallion Express or Chit Chats to do so cheaply though. For Canada, I wouldn't worry too much about tracking unless it's higher dollar value. I regularly sell CDs, DVDs, and Video Games (out of my second eBay store, not the one linked to this username) and almost all of them are sent in a bubble mailer via oversized lettermail in Canada. I've had basically no issues with fraud. Maybe once in about 600+ sales, and I'm not even sure about that one. I haven't been selling trading cards so I can't comment there. Realistically, unless what you're selling is very rare, the extra cost for tracking those types of items in Canada will make them virtually impossible to sell. You're better off potentially taking the odd loss and making sales imo. If the dollar value starts getting higher, you can choose to send it out tracked if you're uncomfortable (either as a parcel or by registered mail).
CDs tend to be slow sellers, so be prepared for that and don't get discouraged.
