How much do you give a baby when feeding baby food?

ok how much should i give my son on the baby food and i know he is not allgic to carrots or bananas so can i give him a little of both. he is about to be four months in 10 days is just completely draining me on milk. and still seems a little hungery after eatting for 30 mins i know i'm still producing enough cas he would not gone from 14.9 to 15.1 in a week. but any ways. that is my question. oh one more if i want to give my son some formula like wen he is ot with me but hee wont drink it is there any way to like trick him. like he dont like the bottle...