My two year old dog ate some bug poison.?

My two year old dog ate some bug poison this afternoon. I noticed when I stepped outside by his dog house and he didn't get up. He usually runs to me so it seemed a bit odd. I tried to get him to stand up but he refused to. Then I really knew something was wrong. He did attempt to stand and walk but he just trembled and struggled. My mom noticed that he had ate bug poison that blends in with the dirt but he obviously must have picked it up even though he never eats or rolls around in the dirt, he just dig holes. Then I found some of it on his bed so then I know it was the bug poison. I took him to the vet but of course the entire treatment/cure was ridiculousy expensive. This dog is my responsibility and I am only an 18 year old college student with a part-time job. So they said that the most they could do with the least expenses is give him a dose that would reduce any seizures and tremors. He threw up at the animal urgent care but he has not since. He came home with me so I am just watching him and I will be taking him with his primary vet tomorrow morning. He is still trembling but he seems to still struggle. He is putting in great effort to stand and walk though. I don't know what to do. No medications were dispensed. Only a dose to reduce tremors and prevent seizures. I just don't know what happens from here. What to wait for. Will he be okay with the simple dose? Or are all those expensive medications absolutely necessary? I am terrified. Thank you so much ahead of time