Welcome Aboard. You've come to the right place. The Marketplace here is a good source for gently used lenses. But be warned, Lens Buying Addiction (aka - LBA) is a harsh mistress.
There's a nice looking one at a descent price on the Marketplace now (not mine):
https://www.pentaxforums.com/forums/photographic-equipment-sale/197908-sale-p...condition.html