If you just need "the lens" find Cloudray Laser on Ebay. Measure the diameter of your current lens and choose your focus distance, normally 2"/50.8mm. They won't last forever if you clean them often but at $30-ish each they cost many time less than the spendy lenses.
If you want a spendy lens, a company called II-VI makes great lenses, but you have to buy the US versions to get the great ones