my neighbor has a really good shop, but probably not feasible given the drive...Lee's on Metcalf and 79th. They are good about pulling up what service is recommended and then helping a person prioritize what needs/must/might need to be done.
Most shops go by what the manufacturer recommends for tune ups...I think you can probably look that up yourself. But Lee will tell you what you most 'need' - so if your brakes are bad he will suggest that say before a transmission service -- unless you are having trouble with the transmission. (He understands that people are on a budget..He will also ask about what your plans are for a car- do you want to keep it forever or do you plan on selling it in a year for example...)
I don't think he would run a diagnostic unless there were some issue ---I am not even sure that he has that particular computer anyway.