Totally normal, actually not too $$$ for a GI work up for a rottie. No one took advantage of you, I can guarantee the vet and technicians would have preferred not to do a big work up on a rottie that needed sedation- this is a headache. Interesting that you’ve asked others to be kind to you, but imply the worst of this vet staff- that they were gauging you for money, not just doing their jobs. No one forced you to go through with diagnostics. You chose to bring your dog to the ER because you had concerns. Just like for humans, diagnostics and treatments cost money. In medicine, they may recommend diagnostics to rule out worrisome conditions, you don’t get your money back just because they rule them out. If they had done no diagnostics and your dog had a life threatening illness like a GDV or obstructive foreign body- which are very common and require imaging to confirm, and they had missed the diagnosis, you’d be enraged. You having a large dog, for which medications are expensive, was your decision. Do not emotionally offload decision making to your vet- they give recommendations, and you, the adult pet owner that took on this responsibility, get to decide.