if you do not get a w-2 for the work you are an independent contractor. you report the income and expenses on schedule C. assets that have a cost too large to qualify for direct expensing, are capitalized and would likely qualify for section 179. you don't need an EIN to have a business. registration is a question of ;local law so see a lawyer if you have concerns. generally, I would recommend getting an EIN. this is in case you need to issue 1099's. then you can use the EIN rather than your SSN.
see IRS PUB for more info on section 179
https://www.irs.gov/pub/irs-pdf/p946.pdf
