How do you link sales and marketing?
Offering 'wide selection, good service, and best prices' is a very common online strategy for retailers. It is also the most likely to guarantee mundane results. Everybody says it and nobody is different. Getting people to understand what it is that makes you different will help them understand why they should work/shop/visit with you. Thus, your brand is your specialty.
This is particularly true if you use search in your marketing mix. As that tactic continues to grow, both in terms of share of online spending and in absolute terms, the competition for general key words will get terribly expensive. To succeed you must focus on (and own) those ideas most closely related to what it is exactly that you do better than anyone else.
While William Bernbach of VW "Think Small" fame was referring to advertising most of the time, his quotes often reflect marketing. This one speaks volumes:
"In advertising not to be different is virtually suicidal."
If you can't find a way to differentiate yourself, then get out of business.