Three of my chihuahua is sick throwing up white foam and won't eat and we have been giving them pedialite and water they keep throwing it up one goes to the water and drinks and they are really weak note they don't have there shots what is causing this

Your lack of veterinary care is the cause....maybe not directly....

Actually, nobody here can say for sure what's causing it but there is one thing that is pretty sure...they will probably suffer and die if you don't get them to a vet.

Why don't they have shots yet? Have they ever been to a vet?

I know, I know...you can't afford the vet....find a way.

As a pet owner, you are responsible for their care and part of that responsibility is taking them to the vet for shots and overall care...and when they won't eat and are throwing up and dehydrated and about to die, it's a good time to TAKE THEM TO THE VET.

Was I too harsh? You probably think so but I am tired of seeing people with animals that are willing to let them suffer and die slowly. You take the responsibility of caring for a living thing, you need to follow through....and asking on the internet will not cure this no matter how much you ask.

There is a lot of info missing here, but having that info wouldn't change my answer.
Your pups need to see a vet.
Chihuahuas are small and have little reserve, if they are puppies they are at even greater risk for dehydration. Given that it is three and there are more it may something that is likely to spread through the whole dog population at your house. How many dogs do you have?
I understand that funds may be limited this time of year, but you need to find a way to get them checked by a vet.
Borrow from family or friends, sell something, call your local humane society and inquire about programs that help in cases like this. Surrender them to someone who has the means to properly care for them.
Pets are not property, they are a privilege and a responsibility.
It's up to you to do right by them.

It never ceases to amaze me that people think they'll find a cure for their dogs illness online. It won't happen, no matter how much you Google, how many sites you join, it won't happen. No vet can diagnose an animal online any more than a doctor can diagnose a human online. It's not possible. Without tests, without seeing the dog (s) there's no way to even accurately guess what's going on.

In other words, if you're concerned you need to take them to a vet. That's the only option. While you're there, get them their shots. That's part of your responsibility as a pet owner.