Anyone with a 3' by 5' area (that can literally support a ton of water/gravel/etc.) can have an aquaponics system for well under $1000. That's under $1000 complete with lights, fish, and rocks (most experts recommend home aquaponicists stick to rock-based systems).
The Aquaponics USA miniature Food Forever Growing System gets you a plumbed tank/grow bed and accessories for under $1000, but that doesn't include shipping or rocks. They also don't consider lights - a must for us indoor aquaponicists in climates with limited outdoor growing seasons.
As shown in the picture above, the oblong 50 and 100 gallon tanks can fit inside the corners of a 2'x4' rectangle. This means I can use readily available heavy-duty shelving to support the grow bed. Home Depot sells Edsal 2'x4' heavy duty shelving for under $80.
Turns out there are various sources for 100 gallon and 50 gallon tanks. I was able to find Rubbermaid stock tanks at my local agricultural center (Southern States in Manassas) for less than $70 each. They're 52" by 31" and 26" high for the 100 gallon, 12" high for the 50 gallon.
I liked the gray granite of the Behlen 50 and 100 gallon tanks, but couldn't find them at a local vendor. If I lived near Austin, Texas, I could get tanks from Plastic-Mart, but the shipping costs were prohibitive (much more than the very reasonable item costs). Any other tank is OK as long as it is made of food grade material and fits inside the 2'x4' support post locations.
Below is the rough order estimate for the system components, including water, pump, bubbler, lights, fish, rocks, and plumbing:
$050 Air pump and bubbler
$050 Water pump and plumbing
$150 Stock tanks (locally-sourced 50 & 100 gal tanks)
$080 Heavy duty 2'x4' shelving
$050 River pebbles (14 bags @ $3.50/ea)
$150 Flourescent lights (20,000 lumens)
$650 TOTAL per complete 3x5 fishtank/growbed unit.
Take away the fish, lights, and rocks to put this concept on par with other systems available for sale, and we're talking less than $350 - a number even a skeptical spouse might like. Being the holidays, they could buy it for you without having to travel further than the local agricultural coop and Home Depot...
To add growing space, you could add additional growbeds/shelving/lights for only $400 each . So the three growbed system shown above would cost $1450. Ongoing costs would be seeds, electricity for the pumps and lights (~$80/year in my area), and fish food (~$20/40 lb bag at the local Southern States), plus a bit for replacing parts that wear out (light bulbs, pumps).
For the rest of 2010, I'll take you along as I construct a basic 3x5 aquaponics system, in preparation for adding tilapia in January 2011.