What you should read depends on what type of writer you want to be.
First, you should read what you like and lots of it. You are not reading to learn how to write like Tolstoy, Faulkner, or Twain but to learn what type of writing to which you respond and to make you better at writing like you.
When you are ready to tackle the professional markets, you need to find out what they are buying. For short fiction markets, many publishers make their stories available at no cost.
Other markets offer a sample, which can still give you an idea of the feel and style the publishers are looking for
This is only a small sample, but it will help you get an idea of the quality of writing that publisher’s are expecting from authors.
Entering and reading the stories from motivational competitions, like Motivation Mondays can be very helpful. Bear in mind that these are usually unedited or casually edited drafts. Most editor’s expect perfection, and whether your grammar and punctuation are perfect or not, they expect you to knock their socks off.
Be awesome! And keep writing my friends!