I've had two joints quote me different prices for the Big Mac since their free small coke and chip deal.
How Much Does a Big Mac Cost at Your Most Frequently Visited Restaurant?

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 - Mcdonald's don't classify themselves as a restaurant for tax purposes - In a legal battle that is likely to see dozens of other fast food chains in the world's largest country following suit, McDonald's successfully argued that it should be classified as a food retailer for tax purposes rather than as a restaurant since many of its products are pre-packaged and sold to customers in the style of a supermarket rather than a restaurant. - It is a decision that will allow McDonald's in Russia to continue paying ten per cent tax on its profits rather than the eighteen per cent tax levied on restaurants. - So yeah, don't call em' a restaurant, call them a 'food retailer'. 
 
 - Maccas isn't my most frequently visited restaurant, but for the most frequently visited Maccas, St Peters Maccas on Princes Highway sells them for $5.20. 
 - I thought the prices were the same at all Maccas (in the same city anyway). My local charged $5.30, another Maccas 15mins drive away charged $5.20. I used the Maccas app for the $5.30 one though (for the $5 off), not sure if that makes a difference. 
 - $5.45 in Jolimont, WA. 
 - i swear i just saw it for $5 in wynnum! 
 - $5.20 at my local store. Others in the area go up to about $5.40. Quite a change from around ten years ago when I remember seeing them for $3 :) 
 - pro tip: download the mymaccas app. Select the store you want and lookup the price for a big mac :D 
 - $5.60 at Sunshine Coast QLD 
 - 5.05 at a few maccas in vic 


My most frequently visited restaurant doesn't sell them.
They have lunch specials though, just under $10.00 for Pad Thai.