Have you used a vet for routine care as opposed to an emergency clinic? Emergency care is generally significantly more expensive than routine care. You might call around and check cost for a visit during regular hours. Also ask if there are any low cost clinics in your area.
Chronic vomiting can be a sign of inflammatory bowel disease, which is common in cats. Wheezing can be a sign of asthma. Many animals with these diseases can be treated and live reasonably normal, good quality lives. The cost of some frequently prescribed drugs is relatively inexpensive.
If you are not able to afford the cost of the work up and drugs and if your cat is suffering, euthanasia (putting him down) is an option to discuss with the veterinarian you see during normal working hours.
Let me know if you have follow up questions.