Just because you can afford to rent an apartment doesn't mean you're qualified to. Most landlords will require that your annual income (OR the combined annual income of you and your roommates) equals at least 40-45 times the monthly rent.
For example, to rent a $3,000 per month apartment, your annual income will need to be around $120,000. You should also expect to have your credit report reviewed. Most landlords will be concerned if you have a score under 700 (out of 850), and/or you have a history of late payments, judgments, or bankruptcies. In that case, you may not qualify for an apartment without an additional security deposit or a guarantor.