Baby cereal and formula?

Rachel
So baby is just about 4 months and I'm dying to start giving him some food because he's so interested 😂
I was planning to mix the rice cereal with formula because I don't get to pump much with this hungry boy, and when I do I like to save it for emergencies 😅
What is the best formula for this, or in general?
I used enfamil newborn when babe was just a few days old before my milk came in, but it has since expired, and I couldn't stand the smell of that 😩