How much should I expect to pay for an x-ray on my labrador?

I have been advised that I need an x-ray on my 6 year old male labrador retriever to investigatre his stomach pains. he has had blood tests and urine tests that are all clear and has been taking antibiotics. But I now have to have him sedated and x-rayed. I hve been quoted a price but want to see whether it is overpriced. can anyone let me know how much I should expect to pay.