In the past few days, I've received a couple of little things I found on EBay.
For Polaroid SX-70, the tripod adapter and remote shutter release. $50
For Hasselblad 500CM and 80/150mm lenses, a small collection of B50 close up lenses. $45
It's amazing how much versatility and quality improvement can come from such small expenditures! Now the relatively limited close up ability of he Hassy's lenses is no longer a problem, and the Polaroid's slow film is similarly less a restriction since the camera can be well stabilized.
Anyone else find some little gems like this that opened up new dimensions in their equipment?