Placing orders without taking payment for select customers

Is it possible to have certain customers place orders without requiring payment? I can't find a way to do this. I have searched hard on this site but not found the answer.

I have certain customers who will submit payment to me in person, but I do want them to be able to place their order through my Zen-Cart store.

I tried setting up a 100% discount, but shipping costs were still added, and I don't know if selecting a payment option can be bypassed.

Please let me know if you know how to do this.

I am using the latest version of Zen-Cart, and I'm using PayPal IPN standard, and VM CC payment gateway for payment modules. Canada Post and UPS for shipping modules.

This is what I use
Works well for me :)
http://www.zen-cart.com/index.php?main_page=product_contrib_info&products_id=230

Awesome! Thanks SO MUCH!

That worked like a charm.

Anytime :)

Now another issue has come up - it is now needed to also bypass the shipping. Any suggestions on how I can do that as well? This should only be for those who pay by invoice.