How much would it cost (approx) to change the front brakes on 93 honda. I get different estimates from different auto services ( ranging from $250 to $550). Can anyone shed light on this?

I'm not sure what they charge, but get them to change all of the brake fluid when it's done. Also, don't let them automatically turn the disks--it can cause lateral runout, since they turn them to the lathe's axis and not the spindle's. I recommend you use either Honda pads or a major brand formulated the same as OEM. There are a lot of junky pads out there.