I started planning a budget sump to fit in the cabinet below my 55 gallon that I can assemble next summer (or sooner if I get antsy), but right now I'm trying to find an inexpensive sump tank. I've checked e-bay, craigslist, etc, but they all seem to be pretty costly. Plus, I only have 11-inches depth to work with in the cabinet. Question 1: where can I find an inexpensive sump tank that would fit in this space?

One idea I had was using a small aquarium. We have a grocery store that sells bare 10-gallon tanks for $9.99, bare 20-gallon tanks for $19.99. The problem is the 10-gallon, I'm afraid will be too small (I'm hoping to add a refugium) and the 20-gallon is too deep for the cabinet. Question 2: could I put two 10-gallons side-by-side and cut overflow holes in the sides and pvc them together essentially creating a long 20-gallon sump tank?

Question 3: Am I just being too much of a tightwad?