No seriously, I just looked on ebay and amazon and can no longer find a replacement lunchbox air filter. I know even with a good cleaning, its looking pretty beat. Any have a good source?

This won't work? - https://www.ebay.com/itm/223683762843?fits=Model%3AGS500E%7CMake%3ASuzuki&epid=1328567023&hash=item3414975a9b:g:gY0AAOSwgMdlHR-N

The lunchbox filter is a K&N RU-2970. A quick search shows it for sale across the internet including eBay and Amazon (but just say no to Amazon).

You can find it many other places:

https://www.knfilters.com/ru-2970-universal-clamp-on-air-filter

https://www.summitracing.com/parts/knn-ru-2970?seid=srese2&utm_source=bing&utm_medium=cpc&utm_campaign=Brands+|+K&utm_term=4582077271688017&utm_content=GSAPI+5ba287eed9cc7