If you need a few key rings but will not order 50 or 100 pieces, it's right here. You get a few euros (shipping free from Amazon at a total bill of about 20 euros) a set of 15 key rings.
Especially the 3 large flat rings are of high quality, visually appealing and provide a good basis for a set of keys.
Desirable, however, would be smaller rings (with better quality), to form key groups.