Is there any type of cheap filter media i can get, along the line of bio balls to stick in my sump and under my trickle filter!?
Cheers!

Fishing line is popular, havent tried it myself but having been around a few sites it is quite common. Couldnt tell you if theres a down side to using though :hmm:

You can use just about anything with a lot of surface area. Some of our members use lava rock or the plastic ends from manufacturing. I imagine that you could even use plastic silverware.

i use lava rock. you can also use plastic army men.

One I've heard recently is the cheap plastic pot scrubbers from the dollar store.

I'm seeing lots of good suggestions here so I pinned it. jay
Keep them coming!

I've heard plastic batting from quilts! Supposed to be really cheap for lots. :)

I used some bits of plastic, supposedly from bioball manufactuering, myself.