Opening a store?

I  think having a bit of extra income is a good thing. But how to get it?
What about opening an store on line? This is something I am thinking about, but afraid to try. So readers, please let me know your thoughts.
I would sell stuff  I made by knitting and when I get better crocheting.  Is there a big market for that? Yes or no? Please let me know what you think readers.