hi friends i am using adwords for selling products on adwords i wanted to know that whether direct linking to advertiser website cost be high or it does not matter
Doesn't matter. Adwords is a system of "every one is on equal footing". You are rewarded based on the quality of campaigns you produce and nothing else.
By direct linking, you don't get a chance to bring down your cost per click through landing page QS. If someone else is also direct linking the very same product as you, and they have a better ad rank than you, your ad won't display. You're basically missing out on traffic. Take the time to build a relevant landing page that gets the visitor into buying mode and lower your cpc. A lot of CB landing pages are very ordinary.
> How does having a landing page lower your CPC? It doesn't. It's having better quality that lowers your CPC. That's what the QS system is all about: Quality of your ads. The quality is calculated in large part by your CTR, assuming your keywords are relevant to the landing page. If you use "wedding dress" as a keyword to a page that sells basketball shoes, you won't have good keyword relevancy. And displaying an ad about basketball shoes when I asked for wedding dresses will not get many clicks. Lower CTR, lower QS. That's logical but many advertisers do just that. If the landing page is about wedding dresses and "wedding dress" is the keyword, you have half the battle won. Your job is then to convince them to click your ad. That's the hard part. QS details in free Adwords FAQ.