Ignore manufacturers' recommendations for replacing filter pads. They often want you to drop ridiculous amounts of money per month on maintenance. Just rinse your old filter material in water you've removed from the tank during a water change, and put it back in.
Some commercial filter pads, like for the Marineland line of filters, have become flimsier and now disintegrate over time, probably to encourage people to buy more. A lot of people adapt filters by filling them instead with sponge material that lasts indefinitely.
All my substrate is always sand from a hardware or pool filter supply store. I have play sand now but miss the pool filter sand I had previously, because this stuff compacts too much. All my rocks and wood/driftwood are collected from outside.
I have gotten tremendous deals on beautiful, healthy plants from forums like this and local aquarium clubs. There is no comparison with the stores. Goatnad on this site sent me the nicest group of plants I've ever received, for the lowest cost I've ever paid.
Use dry fertilizers for plants and mix them yourself instead of buying the expensive liquid type. I haven't done this yet because I am lazy, but I plan to next time.
Always question any recommended chemicals or additives to address aquarium problems like algae and many illnesses. Many early problems can be solved by making sure you have clean water and the right lighting schedule. Treat ich with heat if you can.
Monitor your local classifieds/Craigslist for free stuff or great deals. There are always people giving up the hobby or moving, and lots of fish being rehomed and supplies being given away or sold cheaply. I have purchased nice, used filters off Craigslist and Ebay, but you do have to be careful and read the descriptions carefully. I purchased what I thought was an Aquaclear 110, but it turned out that it was an Aquaclear 20, listed in the headline as 110v, meaning 110 volts. No mention of the 20 in the ad. I couldn't ask for justice, because I was the one who misread.
