Newsprint is virtually anything that is offered in a hard copy of print. This can include newspapers and magazines. Either of these can be general or product specific.
It will really depend on what you are putting into these publications as to which ones you want to use.
If you can find a specialist magazine that deals with the subject of the product you are selling then it would be an excellent idea to advertise in that publication.
You should make your starting point a news vendor that carries a large range of publications andsee if there is a publication that covers the subject of your product. If there is then you need to purchase a copy of the publication and look at the prices of placing ads.