For years I have sold thing over the internet on the large auctions
site(s).  I have been successful and always watch my margins.  After
paying fees and shipping the margins sometimes get thin.  My question
is how do I get discount shipping from DHL, FedEx, UPS, etc.  I have
called and asked for my rates to be lowered and they did lower it once
by about 2%.  Not so great.  I am looking for deep discounts like
large companies get.  I know the company I work for can ship the same
exact thing for about half to a third the cost.  Is there a co-op or
some type of on line service that can help with this?  Is there a
secret that will convince the large shipping companies to provide me
deep discounts with out promising them I can ship thousands of
packages per month?

Chadhen,
I think you have put your finger on the problem:  not being able to
promise that you will be shipping a great many items each month.  If
you were able to, you would have the clout to bargain with the
shippers, threatening to take your business to a competitor
(interesting what you say about their costs).
But without that promised volume, they have no incentive to give you
more than a token discount; it's bad for their business.
I am sorry that I can't offer you a more helpful comment.
Myoarin

Try talking to a local independant Mail & Parcel center. I own a
center in Arizona and we work with a number of ebay sellers. depending
on the volume we often give up to 25% off in order to capture the
business.