It has been a few years since I populated passenger cars and I remembered thinking that what I had at the time was inconsistent. This time around I have about 10 cars to do and thought I would try to document the bang for the buck comparison. "For your consideration" (as Rod Serling would say), here is what I purchased, ranging from $0.75 each (K-line set on the big auction site) to $0.18 (on the big river site) for comparison.
The first picture shows examples of the two figures, the expensive ones are on the right, cheap on the left. Both are advertised as 1;48. Size matters but the ones on the left look ok in the cars (even if I have to amputate some feet, occasionally). I can use a sharpie to add facial features at the cost difference. The trick obviously is don't sit them next to each other in the same car to accentuate the differences.
My conclusion is to buy cheap; the difference at 4X is not worth it. If these were going on park benches, my conclusion might be a bit different- but probably not at this cost difference.