You can use standard gelatin (used for jellies) as ballistics gel. It
isn't quite the same grade as the real thing, but if you are doing this at
home, you don't need extremely exact precision. It's like the difference
between 89 octane gasoline at one gas station and the 89 octane gasoline
down the street.
As a forewarning, it is still somewhat cost prohibitive. A single batch
could cost $45 in gelatin.
Here's the trick: just go to Wal-Mart or wherever and head to the Jello
and pudding section. Look for Knox unflavored gelatin or Kroger unflavored
gelatin. It should be a little box that is 3" x 2" x 4". Both brands are
100% pure USP gelatin powder. The only difference is in the chemical
tolerances for the consumer and scientific market, and even that is probably
negligable. You can get boxes that are larger or smaller, just make sure it
is gelatin powder and you should be fine.
Get 6 boxes (about 36 oz / 2.25 lb / 1 kg) of gelatin
and 3 gallons / 9 liters of distilled water per block you want to create.
Then head over to the Ballistics Gel
section and follow the instructions there as though you had the