If you are have something to sell, then you can sell it on the web. Any imaginable item or service can be bought and sold on the web, there are opportunities that can be had in almost every market, just take a look at the major auction sites, every now and then they break new ground with items that are up for auction that only a few years ago would be unheard of.
If you are thinking of selling an item here are some tips.

Do some research? See if that item is already being sold, check out the competition.
What price are they charging, how much is shipping and what services are they including. Your competition can be your best source for ideas so visit them frequently and learn from them.
Don’t be frightened by competition, remember to do comparisons in regards to your products or services so you can differentiate yourself from your competitors.

Try multiple channels for your product, such as auction sites, independent web sites andaffiliate site directories. They are all very inexpensive to enter and you can determine which channel is the right place to sell your product. For instance if you are selling cellular accessories, you might find that eBay brings much more traffic then an independent site would bring.
For ebooks, you might look to an affiliate site that deals in downloadable media. Choose your channel correctly and you will profit.

Decide whether you would like to wholesale or retail. If you can purchase mass quantities of products cheap enough then wholesale opportunities might be better for your business.
For instance, you might find having 10 buyers a day is easier then 100.
It’s all about testing and more testing, what works in one market may not work in another but by analyzing your results it will soon become evident as to what is more successful.
Find what works for your specific items and maximize the products strengths. With enough analysis and research you can sell any type of product on the web.