OP - follow your instincts, and none of the advice that you have read in this thread until now. A bark collar will stop a dog from barking. But the reason that the dog is barking will still be there, and the dog will become more miserable now that he can't even bark. He will start to chew things up to get attention, piss all over the house, or even chew holes in his own legs and stomach out of frustration. <--- yes I have seen that happen.
Your dog obviously suffers from separation anxiety. This is a common behavior and can be fixed. Just google for it, read some books to find different ideas to try, or if you really want to have a happy and healthy dog, register for some training classes. It makes a world of difference. And I don't mean sending your dog off to school expecting him to come home knowing how to act. A proper trainer will teach you how to train your animal. And if you you are worried about costs, the expense of vet bills from the dogs worsening state, household in an uproar all the time, and finally having to drop your dog off at the pound because you were too cheap or lazy to learn how to train it properly will probably take a larger toll in the long run.
You can train nearly any dog on the planet to behave exactly as you want it to 100% of the time if you know how. The problem is, people don't spend the time and money to learn, they just start zapping the piss out of it screaming SHUT UP DOG!
And they wonder why they get bit.
For the record, I do have an electric collar that is part of the training gear for my Shepherd. The sole purpose of the collar is not to teach the dog, but as a last resort in case the dog's instinct kicks in and he ignores me when I tell him to unclench his teeth from your arm or throat. Saving your life is more important than not hurting the dog.
Spend a couple hundred bucks and go to a trainer who will train you to properly care for your pet.