It largely depends on the size range/s you want. There are adjustable reamers but they're also rather expensive, and normally only cover a range of about +/- 2 mm. But they are fully adjustable to any dimension within the stated range, so if you only want "a few" diameters they COULD work out a bit cheaper than buying individual (single size) tools.
Personally, wherever possible I try to "design" any job of mine so that it uses one of (the few) existing reamers that I have.
Remember the first hole you drill a hole is just a hole to remove the majority of the metal, you then open up the hole to a size that a reamer can accept. The reamer removed just a tiny amount of material. Plus ideally it want to be done in a bench drill and the work not moved between the drilling stages and the reaming itself for best results.