Thank you. Since we don't know what we are dealing with the best thing is very conservative treatment. Take up the food AND the water--if he is vomiting we need to get that stopped and he can go without water for a short period. Withhold water for 12 hours. If he has stopped vomiting in that time, then you can reintroduce JUST the water. Give small portions at a time (1/4 cup or less every few hours). Give only water for an additional 12 hours.
If at the end of this 12 hours of water only he is doing ok (no more vomiting and seems to be acting ok), you can start feeding a bland diet (boiled chicken or hamburger and rice) again in small portions given frequently. Feed the bland diet for three days if he tolerates it well. At the end of three days, if he is recovered, you can start reintroducing his regular food.

Unfortunately, if we don't know what exactly is wrong, or what he may have gotten into, there is little else we can do for him. I do understand you financial concerns, but if the above doesn't help, or he gets worse, you may have to have him seen.

I hope this helps, please let me know if I can answer any other questions.