What percentage of website traffic should be buying products?

I have found most of the cases experts take 3% to calculate . I think it also depends on the situation . How much money you need to spend and how many traffic you are getting for that . To recover your expenses how many sale minimum you need is the key

What you are referring to is conversion ratio. Conversion ratio can depend on a lot of factors, including but not limited to the nature of the product and how targeted the traffic is. For many ecommerce websites 5% is a good ratio to work with. I've had projects with a lot higher conversion but then we'd have to discuss in a lot of detail as to how targeted the traffic was and the ticket price and merchandise category etc etc.

Unless your single order is thousand dollars a pop or so, for general use items generally $20 or under per item/order, 5% is a good rate to shoot for. If I can give you one suggestion in this regard, that would be to take a very close look at the quality of your traffic. Many times there is a day and night difference in conversion depending on how targeted, motivated, and qualified the traffic is. Best of luck and keep aiming higher.

We have extremely targeted traffic. Over 80% of our search engine visitors are searching for my brand/company name in particular. The majority of traffic from links comes from positive reviews other people have written. I just started a blog on the site so I see the blog is getting the most traffic (I'm writing high quality articles and posts and running contests). Is there a way to help convert the blog traffic to make purchases?
The average sale is around $15-$40.00

So, knowing this about my site (I really don't want to post it here) Is there anything that I need to look at to increase the conversion rate? There's also a few abandoned shopping carts. I know that's normal (we have more sales than abandons) but what factors go into that that I can fix?
I just had my site re-done professionally by a marketing company so I'd like to know if they missed anything I can fix. Compared to the other top sites in our main searches that we rank for we by far have the most professional website that (I think) is easiest to use. I know I am out-selling my competitors (I know exactly what they make) but I want to do better! Are there any good articles on conversions that I can read?