The best "reamer" that I ever used to control cake -was a piece of sandpaper wrapped around the proper size wooden dowel. Saw a vertical slit on one end of a dowel and roughly round off that end with a file to capture a strip of sandpaper. Never got a chip, never got an unwanted gouge...and the hardware store always has sandpaper and various dowels stocked on the selves.
A lot cheaper than those classy reamers that twist and break.
Same. I don't buy a tool unless I think it's necessary, and I just haven't seen the need with pipe reamers. My cleaning practices generally prevent the buildup of much cake, and when I've had a caked up estate pipe, I also found sandpaper to be a good solution. I just used a wooden pencil wrapped in a paper towel to get the right diameter, then wrapped a piece of sandpaper around that. Worked excellent to get rid of most of the cake, and I tamed the rest with paper towels and grain alcohol as well as one of the dull folding reamer blades that come on some pipe tampers. Now if I was constantly reaming pipes as a part of a restoration or repair service, then I'd get a good reamer set.