I am a USA based company. We want to buy BLANK plastic ball point pens
from China. We will then screen print them in the USA and sell them in
the USA. I have found a factory in China and I know all the shipping
costs for it to be shipped to the Los Angeles Port. What I cannot find
is the tariff/duty is on them(from China to L.A.). That is what I need
to know...

this may help and then agian it may not but take a look at it and it
might get you to where you need to be.

http://www.newsgd.com/news/China1/200412230049.htm


http://www.ncseonline.org/NLE/CRSreports/Economics/econ-35.cfm?&CFID=232119&CFTOKEN=84139235

Have you tried the U.S. Tariff and Trade Data database

http://dataweb.usitc.gov/scripts/tariff2005.asp

Just joined and hadn't read FAQs on answer and comments so
here it is for free!!

Pens with ball point are classified under the 
Harmonized Tariff Schedule of the United States (2005) this can be found on
http://hotdocs.usitc.gov/docs/tata/hts/bychapter/0500C96.pdf
The code of the item is 96081000

Keying this on the database for tariff 
http://dataweb.usitc.gov/scripts/tariff2005.asp 
we get the list of tariffs that apply to various category 
of trading nations. In the case of China they are now
member of the WTO and enjoy "Normal Trading Relations" NTR

This is taken form the URL for your product:
....................................................................
Duty calculation ((Specific Rate) x (Q1 - ie number of items)) + ((Ad
Valorem Rate) x (Value))
Ad Valorem (percent of value) component 5.4% 
Specific (per unit) component $0.008 
Other duty component $0 
Binding Status Bound in World Trade Organization 
........................................................ END

So if you import 1m ballpens at $0.10 each the total value
of your order is $10,000
Specific component of the import duty is $0.008 x 1m = $800
Ad valorem component is 5.4% x $10,000 = $540

So Total duty = $1,340 using the figures as an example.

OTHER ISSUES

There can be special duty to protect the US against anti-dumping.
see http://prototype.usitc.gov/trade_remedy/731_ad_701_cvd/investigations/completed/index.htm
Checking this shows certain products do have
apecial treatment ruled on by the President but
not for Pens.

Finally, you should check these details for your product with
the Bureau of Customs and Border Protection of the Department of
Homeland Security as they are responsible for interpreting and
enforcing the HTS
- import duties.