Need to encrypt a file? Don't have any budget to buy software? You don't need to really, there is plenty of opensource stuff out there and some built-in stuff to. Give openssl a try on Mac OS X.
Encrypt
#!/bin/sh
in="$1"
out="$2"
openssl des3 -in "$1" -out "$2"
exit 0
Decrypt
#!/bin/sh
in="$1"
out="$2"
openssl des3 -d -in "$1" -out "$2"
exit 0