The most obvious possibility omitted is that your wife got the first, easy, cheap car and then Uber had to quote you a higher price to get a second car. Cars don't fall from the sky; if two people successively ask for bids, how else could it work? What if the app quoted you both the cheap price for the only car within X blocks, and you bought it before she did? Is it suddenly going to go 'oops sorry, changed my mind, it now costs twice as much'? Sounds like a very bad experience to me! More sensible to give the first person a low quote and then when - unexpected and unpredictably - someone requests something similar, quote them the higher price reflecting the sudden local micro-shortage.