My dog for the past two days has lacked energy and is sick. A few days ago, swelling occurred right away out of nowwhere and looked like the dog ate a tennisball from the swelling. The swelling started from the bottom of his throat and has moved now up to his mouth causing him not to be able to open his mouth. The swelling looks as if he swallowed a bunch of tennis balls and they got stuck in his throat. I tried touching the swelling and my dog let me. It is squishy but also big. What could this be? Please help.

It's possible it is a bite or allergic reaction to something, swelling can last few several days if the dog has had a bad reaction.

What concerns me is the fact he cannot open his mouth, can he drink? How are you keeping his fluids up?

As it has been getting worse, not better, you need to get him into a vet asap!

Well I've been trying to get him to drink but its hard with his throat so swollen. It falls out the side of his mouth but some goes down. He lying on the bed currently. His breathing is light in the case the vet is too much money.. what can I do?

If he is having trouble breathing then the only thing you can do is take him to a vet.

I know money is tight for a lot of people at the moment but this is something that really needs veterinary attention.
Have you been with the same vet for a long time? Quite often vets will allow long-term clients to pay the bill off in installments.