How can I create my own loops?

[chaaaaaa]

What program(s) do I need to use to create my own loops?
Approximately how much will it cost?
I’m currently using Acid Pro 2.0. I want to use Acid’s interface, but I want to make my own loops instead of using pre-made loops Acid offers.

How can I make my own loops?
Where do I start?

Thanks!