How much should I feed my 7 month baby boy per day?

I am sure he will let you know, my little girl eats 5-6 ounces every three hours, then at night I give her cereal because it helps her sleep. She is only four months old, but her cousin is seven months old and he eats a little less than her, so it completely depends on the baby, but I have never known a baby to not let their mommy know when they were hungry. If he isn't eating regularly you should tell your pediatrician.

Gerber has a lot of good info you might want to check. Here is a link to some sample menus for children your age to try: Gerber > Start Healthy > Feeding Plan > Menus

I have 6 children and this was the menu for mine at 7 months:
Breakfast: 1st stages fruit/cereal/4 oz milk
Snack: 4 oz milk
Lunch: 1st stages fruit/1st stages vegetable/4 oz milk
Snack: 4 oz milk
Dinner: 1st stages vegetable/1st stages meat/4 oz milk
Last bottle before bed: 8 oz
They all were right on target for age/height/weight, never over or under weight.
Hope that helps.