Re: Internal Auditor Training
Welcome to the Cove!
If you're new to ISO, I am not sure you will manage to obtain all three at once: quick, economical, compliant. You will need to start at the beginning.
A quick and economical approach is to read
Google books on ISO.
Following that, an internal auditor should have training in auditing. I got mine with SAI Global, but your local ASQ section may have more economical options.
I'd like to say that what is best may not be quick, economical or even simply compliant. If you are looking to help your system's effectiveness and profitability, I would shift focus to value-added. I hope that makes sense.