An excellent post from Andy on negotiating the price down

First, I'll suggest not asking for a price right away. Let the owner brag about how great his business is. Listen carefully. Take notes. S/he's loading you up with ammunition you can use later.
Okay, so how much does it cost you to produce these products? Answer: about $5000.

How loyal are your subscribers? Very.

Since this list is heavily tied to your name - why wouldn't most subscribers leave with you? Oops.
...and much more.

Do have a read. Some fantastic tips in there!

Can you actually get a seller to reduce his price? Or is it the case that they never budge?