Here are some links to our online stores stocking pyrite ammonites. They are all found on Charmouth beach, Stonebarrow on the Jurassic coast. 

Jurassic_coast_ammonites - eBay. 

Here you will find a selection of pyrite ammonites both on offer in auctions and buy it now. 

Ammonitefossil - Etsy shop

A selection of pyrite ammonites with hole drilling options for jewellery. 

If you are looking for something which is not listed then do get in contact - I may be able to help.