@wonderspark, I'm not kidding. See screen shot below. The "sort by price" feature is definitely gone. As for the slider-scale for price, over the last few weeks, it seems to come and go. I suspect AirBnB are experimenting with their code. Sometimes the price-slider is there, sometimes the increment-price is there.
I think, with the increment-slider coming and going, AirBnB might be testing the market to see if there's any outcry. Remember, if people are prevented from finding the cheapest accommodation, AirBnB makes more money since they take a percentage cut, not a fixed fee.
The incremental steps are so great that the AirBnB site now forces the users to scroll through sometimes dozens of pages, because the rents that are in your price range, are now jumbled up randomly with rents in significantly higher price ranges.