Why is my refund so low? My friend makes only a little bit more then me and is getting hundreds of dollars. Why is my refund so different?

Something is different between you and your friend.   Maybe your friend had more tax withheld from their paychecks.  Did you friend claim a dependent child?   Is your friend the same age as you?   Did your friend get earned income credit?   Did you get EIC?   You would need to print out your returns and lay them side by side and compare line by line to see what is different.

One thing that pops out is you being classified as a statutory employee (SE). That seems wrong if your job is a cashier. A SE is supposed to be an independent contractor that files schedule C 

as of now it's not costing you anything more in taxes because the company took out taxes  boxes 2, 4 and 6

on w-2

here whom the IRS says are SEs

If workers are independent contractors under the common law rules, such workers may nevertheless be treated as employees by statute (statutory employees) for certain employment tax purposes if they fall within any one of the following four categories and meet the three conditions described under Social Security and Medicare taxes, below.

• A driver who distributes beverages (other than milk) or meat, vegetable, fruit, or bakery products; or who picks up and delivers laundry or dry cleaning, if the driver is your agent or is paid on commission.
• A full-time life insurance sales agent whose principal business activity is selling life insurance or annuity contracts, or both, primarily for one life insurance company.
• An individual who works at home on materials or goods that you supply and that must be returned to you or to a person you name if you also furnish specifications for the work to be done.
• A full-time traveling or city salesperson who works on your behalf and turns in orders to you from wholesalers, retailers, contractors, or operators of hotels, restaurants, or other similar establishments. The goods sold must be merchandise for resale or supplies for use in the buyer’s business operation. The work performed for you must be the salesperson's principal business activity.

as you can see cashier does not fall into any of the 4 categories. To prevent issues with filing your employer needs to issue you a corrected w-2 without that box being checked. If they won't contact the IRS

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there are numerous reasons why your friend is getting back more than you. we cannot see either return.

so the only way to understand why is to do a line by line comparison with your friend's return. There is nothing you can do if they say no.

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here are a few reasons but there can be 100's more

a) friend has more withholding 

b) tax credits you're not getting

c) dependents

d) filing status

e) you use the standard deduction while they itemize and their itemized deductions are more than your standard deduction

f) your gross pay is about the same as theirs but they contribute to benefit plans that reduce their taxable wages 

g) personal contributions to tax benefit plans such as IRA, HSA

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