You can't get better than AmyLim on Ebay for IAL. Her prices are great, shipping is fast (they do come from Thailand so don't expect over night shipping), and her communication is top notch.
As for sponge filters.. they're pretty evenly priced throughout. You can make your own but I'm lazy and just buy the pretty pre-made ones. I got mine from Bigalsonline.com because if you order something like $70 in stuff you get free shipping so I just bought a bunch of fish stuff all at once to save on shipping.