Tell us about yourself!
Here's a link from mernetwork with more info:http://mernetwork.com/index/showthread.php?7106
An important question for you is have you ever swam in a tail before? If not, then silicone is not advised. Try your fins out with some fabric or neoprene. Practice with a monofin by itself. Expect a fabric tail to wear out in a year and then if you're ready to move up to silicone, go for it.
Bare minimum, you'll be looking at $500-600 (this price includes a basic monofin). I think Rogue Siren mentions one gallon of silicone. You'll need 2-3 gallons and that's where the greatest expense lies (~$400). And a 1-gallon unit is actually 2 gallons (1 gal part A and 1, part B). Kanti gives a good breakdown on Mernetwork: http://mernetwork.com/index/showthread.php?2089-Fu...I'm getting ready to pour my molds and then I'll just have the silicone to go.Hope that helps.