How much is a tune-up, transmission fluid flush and brake fluid flush for a '04 Mazda Tribute (4WD, V6)?

I have always trusted the place I went in the past but I am a woman and do not know much about cars, therefore have gotten taken advantage of by others and am now wary of mechanic shops. Is $500 for a tune-up with all the fixings reasonable? How about $200 for a transmission fluid flush and $90 for a brake fluid flush? Thank you!