2002 Chevy Trailblazer cost of brake pads

How much should it cost to replace the brake pads on my vehicle?

Could you break it down by cost of parts & labor? A lot of the times I'll buy the parts myself on the internet to save a bit of money.

A bigger question though is. Should I be putting any more money into this vehicle? It needs new tires as well. For the most part it's been a good vehicle for me but am worried about upcoming costs. The check engine light came on today too as my cruise control petered out. I plan to go to AutoZone to get the code and see if a more serious repair is needed. I can't really afford to get a different vehicle right now which is why I'm trying to fix what's wrong.