im trying to get alittle bigger but i dont have money for a gym and all i got is a 40lb dumbbell and the floor to do pushups on im 17 6'5 225lb since i dont hav a bence press i was woundering if pushups will work almost the same i can only do 20 at a time but i do over 100push ups aday well i try to anyway ive just started this about a week ago

i also have another question i dont kow y poeple say only work out once ot twice a week i couldnt do that i work my arms everyday my arms r never soure or tired the next day thats y i dont feel like i need to rest

A guy your size to get bigger will unfortunately need a gym, your arms probably aren't sore because youre only using a 40lbs dumbell which is rather light.
 
If you really can't afford a gym id say save up and get your own weights

what about pushups will i get begger doing pushups because of my size i can only do 20 push ups at a time will i get some pecks doing push ups every day and how many should i do and walking lunges how many should i do of them

I dont have any experience with pushups and them bettering pecs, i use weights for everything i do, BUT, doing pushups will increase  endurance and will gain some muscle, but there will be a point where you will have to do so many pushups to start putting strain on your muscles that it becomes a very calorie consuming exercise, which will make you burn your calories more, meaning loss of weight if you dont get enough calories, just be aware of that, the higher the rep count, the more calories youre using, and each pushup rep wont push you much, i mean lets face it
 
20 pushups, the first 10 you dont really even feel strain, so them first 10 are a waist of calories as its done nothing really, to get muscles bigger you need to lift big, doing pushups will gain you muscle, but it will get to an equilibrium with your body size and you wont gain anymore.

When your doing push-ups your doing 60% of your body weight, you could elevate your feet on something. When I was in the Navy (and not on a fancy aircraft carrier) and didnt have access to a gym. myself and few other shipmates that were into working out would do pushups and situps alot. we also were deck apes and did alot of climbing on things and pulling ropes alot. needless to say I left the Navy with huge biceps about 20" but I dont think you will gain alot of size on just push-ups, allthough if you ever do start doing any Benching continue the push-ups in the mornings after waking up and before bed, believe me it will allways help with the bench...

Get a bench.

i also have another question i dont kow y poeple say only work out once ot twice a week i couldnt do that i work my arms everyday my arms r never soure or tired the next day thats y i dont feel like i need to rest

 
Ok, you'll find the majority of people work each muscle group ONCE a week. That's because it takes on average 7 days for a muscle to fully recover from an exhausting workout. Your muscles dont grow while your working them, but rather when you sleep.
 
You are probably not going high enough on weights, do you feel you push yourself to the max when you do your arms work out?
 
You really need more equipment.
 
And no push ups are not going to give you killer pecs i can easily do them, compared to pressing at the gym, they only build endurance.