Alas. Airbnb is in the same boat with the hotels, official rate. Sucks big time as both the owners and the tourists get screwed over and the govt take half, but they can't accept cash - it's against Airbnb rules. The only way you can pay cash is to know the owner and arrange with them outside of aribnb, but you have to know them wel land trsut them and vs versa, which is only possible when staying long term or multiple times in the same place. Look ate craigslist and soloduenos, they take cash and wil lnegotiate