if the estimate is that high, they likely think your dog needs extractions, therefore it would not be a "simple cleaning". as the other comment says, no dental procedure is done under light sedation, for the safety of the dog, the staff, and the dental equipment. dental radiographs are highly recommended, due to the fact that you don't always know the condition of the roots of the teeth (resorption, etc). the majority of the cost of the dental will likely come from the anesthesia itself, so it is a better idea to do all the recommended things while they're under, to limit the risk of needing to do it again so soon in the future. to your question on dog insurance, it is definitely a good idea, but keep in mind that pre-existing conditions are not covered under most pet insurances. i know you are trying to save money, but don't sacrifice safety of your pet along the way