If you are tight on money, try reaching out to humane society and see if they have references for places with a sliding scale...the emergency vet is far from cheap!
If your poor do not take your animal there..
Not sure about sonogram, but my dog had a CT and radiograph. It wasn't cheap but they were needed. All the staff is great and will explain everything in detail and they have the equipment that many clinics don't have.
I don't have a clue, I've just taken my dog there twice.
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