Are you having a laugh? You want a shop but don't know what to sell? Do you have knowledge / experience in any particular line or product?
Flipping heck, take a look down your high street for some ideas!!! Newsagent, clothes shop, grocers, electrical store, card shop, off licence etc etc etc
Why do you even want a shop? There is a credit crunch on you know, shops are going out of business on a daily basis so I wouldn't have thought that now was a good time to be setting one up!
It depends on where you live, are there any shortages on some services in your area?
I always love a good rummage in a hardware store. You could sell alsorts of bits and pieces, like DIY tools, paints, kitchen stuff, nuts and bolts, needlework items...............the list is endless. If you give a good service and get what the customer wants, you will also get yourself a good name and people will recommend you to their friends.
Here's an idea. Forget the brick-and-mortar shop and think about opening a shop online. For a relatively small investment, you can set up your "shop" on a web page.
As to what type of shop to open, you need to search inside yourself. Take a personal inventory of what your interests are, what you like to do, or would like to learn to do, or what you have talent in. Next you need to do some research and see if there is actually demand for this type of shop. This is called developing a niche.