Reporting this to ebay probably won't get you any results.

And yes, you did accept the price in the first place.

Leaving appropriate feedback will warn others before purchasing.

However if the item was to your satisfaction and received in a timely manner, I would possibly leave a neutral rather than a neg depending on how polite the seller was in her correspondence.

Keep in mind a seller may include handling time and fuel costs to a post office.

Personally if I purchased an item at a great price and the seller made a few extra dollars for sending it to me, I wouldn't be concerned.

Provided it was still packaged well enough so it couldn't be damaged.

Leave it a few days and see how you think about it later before leaving feedback.