Friend, I am sorry that you are having this problem with your dog. Vomiting can be caused by many different medical conditions. It will be difficult for me to determine the exact underlying cause without a hands-on examination and some testing, I am sorry. But, common causes are a simple gastritis, dietary indiscretion, ingestion of a foreign body, infections, etc. to name a few causes. To determine the exact underlying cause she will need a hands-on examination, x-rays and blood work as an initial screening test. I am going to make some recommendations, if she continues to vomit the next step is a hands-on examination. In the meantime, in any case of vomiting the first thing to do is give the stomach time to rest. This is what you can do:
1- Do not give things like Pepto Bismol or Imodium. Start her on Pepcid AC (famotidine) 10mg 1/2 tablet every 12 hours for the next 2-3 days. You can buy Pepcid AC over the counter in any pharmacy.
2- No food or water for 8-12 hours. Need to give her gastrointestinal tract time to rest. Keep her indoors in a cool room when fasting and no exercise.
3- After 8-12 hours offer a small amount of water. Wait half hour, if no vomiting, offer a small amount of rice (50%) and boiled boneless chicken or ground beef (50%) 4-6 times a day. Keep on this diet for several days then wean into regular diet.
4- If she continues to vomit after doing the above she will need to be seen by your family veterinarian for a hands on examination. If cost is a concerned I would look into your local ASPCA or Shelter where they often offer veterinary services at a lower cost.
If she becomes lethargic, continues to vomit while fasting, develops pale gums, abdominal swelling, etc. do not wait and have her checked immediately by a veterinarian for a hands-on examination.
My goal is to provide you with excellent service - I hope I've provided the information you were seeking, if you feel you have received anything less, please reply back as I am happy to address follow-up questions. Kindly rate me when you are done.