Hi Momosgirl-
It really depends on what freelance work you are doing as each industry has fairly common expenses. For example, a graphic designer may have a lot of computer software programs (or subscriptions) that they can write off where as an Uber driver only needs their phone to operate.
TurboTax Self-Employed helps guide you through the most common expenses by industry.
Hope that helps!
Lisa
Here is some IRS reading material……
IRS information on Self Employment
http://www.irs.gov/Businesses/Small-Businesses-&-Self-Employed/Self-Employed-Individuals-Tax-Center
Pulication 334, Tax Guide for Small Business
http://www.irs.gov/pub/irs-pdf/p334.pdf
Publication 535 Business Expenses
http://www.irs.gov/pub/irs-pdf/p535.pdf
You pay Self Employment tax on $400 or more of net profit from self-employment in addition to any regular income tax. You pay 15.3% SE tax on 92.35% of your Net Profit greater than $400. The 15.3% self employed SE Tax is to pay both the employer part and employee part of Social Security and Medicare. So you get social security credit for it when you retire.