You *NEED* to open a business account. Period. Now a vast majority of banks *REQUIRE* you to have an EIN for your business in order to open a business account. I don't see this as an issue since it takes less than 10 minutes to get the *FREE* EIN directly from the IRS at https://www.irs.gov/businesses/small-businesses-self-employed/apply-for-an-employer-identification-n...
Now-a-days there are so many banks that offer free small business checking, there's no reason or excuse for not opening a business account, just as there's no valid reason or excuse for not obtaining an EIN for your business.
