I buy secondhand filters, usually at a vastly lower price than the apparently high figures asked now. I am careful to inspect for damage and only buy the better quality brands. Many shops remove these items from part exchanged or bought in stock and sell them separately, for obvious reasons. There are also usually plenty to be found at camera fairs, some in fact being unused. I did buy a supply of Marumi filters from the previous importer of these, they were, and indeed still may be, being sold at half retail price.