You won't receive a 1099-Misc for this amount because the IRS only requires form 1099-Misc to be sent to recipients when the total payments equal $600 or more.
That being said, you wouldn't file the 1099-Misc anyway...you'd just include the amount in your taxes. Unfortunately, the IRS wants you to report pretty much every dollar you earn. The following link has more information as to what is and isn't considered taxable IRS
What Is Taxable and Nontaxable Income (click here).
You can simply include the $300 as "Other Income" but if you do this then you couldn't deduct any expenses you incurred in the process of making the $300. I know I can only assume, but I'm sure you had some expenses...cleaners, cleaning supplies, gas in your vehicle to get to the house you cleaned, etc...These are deductible expenses per IRS regulations.
So, if you spent any money in order to make the $300...then you'd want to file a Schedule C and list the $300 income along with your expenses.
