Yeah - the differences between drinking in Manhattan and drinking in Brooklyn were pretty stark. When I would go out for a night in NYC, to comfortably prepare for anything (including bars with covers, or cabs to and from) I would take out about $100. I wouldn't always use it all, but it would not be the most crazy thing to anticipate that your night would be that expensive.
When I used to live in Bay Ridge, it'd be half that. (Then again, we could walk to most places, and none of them were the type to have covers). Queens, it was similar. Although in areas like Astoria, and also Park Slope in Brooklyn, the rents are higher, and correspondingly, so are the drink prices.