Salvage yard. Pay the nominal entrance fee, then pocket all the clips, nuts, bolts, screws, small brackets, covers, ect... you can carry. The larger parts you'll have to buy of course.
On my last trip to the salvage yard, I scored those clips, an oil cap with a classic Toyota logo on it, a washer res. cap and dome light lens for my 87 celica, and a cruise control switch and airbag pigtail for my steering wheel swap. All I paid for was the CC switch. everything else fit in my pockets, and small folding tool kit.