can u help me? stp?

seems you are an expert. I am a stay home mom and a dependant of my hu*****and. I helped my friend taking care her baby for 3 weeks last year. Since she need to get her $ back from her employment spending account, she offered giving me more provided I had to claim the income for the tax purpose, since there is no W2, where should I put this $400 in 1040 form? Thank you so much in advance.