Michael,
The Bucks County Aquarium Society meets the first Thursday of each month at the Churchville Nature Center at 7:30 pm.
The Delaware County Aquarium Society meets the first Friday of each month at Holy Myrrh-Bearers church in Swarthmore, PA. Admission is free at each venue. They always have a speaker followed by a small local auction of items brought in by members....Typically hit or miss of what you might be looking for...
There is someone in DCAS that grows beautiful java fern and brings it to the monthly auction....good size lots at great prices but no guarantee it will be at any given meeting.
On May 14, the Bucks County Aquarium Society will have their annual spring auction which typically becomes a 5 hour auction of NEW items donated by Suppliers and Stores/Vendors and donations of used equipment, plants, fish, etc that either the hobbyists have grown tired of or have outgrown their tanks or the fish have spawned and they have no room for, etc.
I can tell you we will have several tank setups (used but in good condition/water tested) available, as well as a good cross section of fish from live bearers to cichlids, plecos, etc. Plants(most of the time) are always abundant as well as driftwood, stones, etc. Everything and anything you can think of.
Both sites have a Facebook page which is no charge to view/sign onto....You can post on there if there is something specific you are looking for and many times another hobbyist can hook you up similar to this site....Typically the auction prices are less than what you would pay at a store and much better quality/health.
Besides knowledge, are you looking for something specific? I was downsizing in the fall/winter so don't have too much extra right now but you never know...