Well you should always commit yourself to every product you offer. But don't commit to just one. Commit to many products related to your market niche.
And always keep searching keeping in mind that the cheapest product is not always the best.
And my favorite piece of advice.... Differentiate or Die!
The net is packed full of people fighting for the same cutomer base.
Find your niche market, find out what they want, give it to them.
And of course spend much time on your supply chain organization and research.