The Macanese Pataca is pegged such that
1 HKD = 1.032 MOP
(Wikipedia).
I understand that HKD are widely accepted in Macau.
However, if an item is listed as say 100 MOP and I try to pay using HKD, will I have to pay also 100 HKD (hence losing about 3.2 percent)? Or will I get a small discount---say I pay 97 HKD only, the fair rate being
100 MOP ÷ 1.032 (MOP / HKD) = 96.899 HKD
Assume I can speak Cantonese and am willing to bargain and haggle a little everywhere, if that can save me 3%. Will I get a fair rate at most places if I insist on paying using HKD?
Edit: After consultation with some who have been there recently, it appears that the folks in Macau quite strictly accept HKD and even CNY/RMB (!) on a 1-to-1 basis, so it is strongly advisable to change your HKD to MOP, if you wish to save the 3%.