I don`t think you will find any one product that sells best. I believe selling is dependent upon how you go about selling it. The main factors you want to hit are keeping your overhead low, so you can keep your final (retail) price low. The more competition you have, the harder it will be to compete. That isn`t to say that people selling products which are saturating the market (online) don`t make money.
Your personal skill of making the sale it what`s important. What are you planning to offer that your competitors are not offering? Better customer service might not be enough. On the other hand, depending on the product industry, that might be all you need to convey.
I know this isn`t much of a concrete answer for you, but really look at the equation of your wholesale price, operating costs, and resale value. If the math works out for you, you might find your product to be a successful venture. On the other hand, you might need to crunch the numbers on several different products before you find the one that suits you.
Just remember this... If you are a fish, and you are the only fish in the stream, it`s easier to find food. If you are one fish of millions, competition becomes more difficult. Doing business online or from a brick and mortar building hold that same challenge. There is competition. If there were not, everyone would flock (um... I should say "school", because of my reference to fish.
) to the new area of instant reward.
Only you can decide what you will be able to sell in the market of competition. That`s why SuN recommends finding a business you are passionate about, rather than one you are just trying to make money. Work is work. Nothing in business comes easy.
Vincent Wilcox (a.k.a. KRAKR)
My band: Letters Make Words