Save 55% on beer this Sunday

How much further? For the cost of eight pints in a pub you could drink 14 pints at home, according to Picardo, a financial analyst for the NerdWallet personal finance site.

(One hopes those 14 would be shared among friends.)

"If consumers spend the projected average of $38 on the beer-heavy holiday, this extreme price gap could be costing Americans an extra $2.6 billion in a single day," she writes in this NerdWallet post.

The $38 figure comes from the National Retail Federation and includes all St. Patrick's Day expenditures: corned beef, green necklaces, et al. But for her article Picardo assumed that the entire $38 will be spent on beer.

After all, one or two pints into the evening some folks start proclaiming, "Next round's on me!" -- which could cost $38 all by itself.

For some, the pub experience is what makes St. Patrick's Day semi-authentically Irish. A survey from Spectrem Group indicates that 58% of people ages 40 and younger will go to bars on March 17.

It's hard to pass up a 55% savings, though, especially when that's just the price of the brew -- overindulging in a public place could wind up costing you in other ways, too.

Party responsibly

All 50 states now define driving under the influence as 0.08% blood alcohol concentration, according to an MSN Money article called "DUI: The $10,000 ride home." Some states have separate charges for lower blood-alcohol levels, e.g., "driving while impaired."

• Bail: $150 to $2,500
• Legal fees: $2,000 to as much as $25,000
• Fines: $300 to $1,200
• Alcohol evaluation and treatment: $150 to $2,000
• Insurance rate hikes: $4,500 or more over time

Note: That $10,000 figure does not include accidents or injuries.

It's impossible to say how many pints of stout it takes to arrive at 0.08 BAC, but for some people it doesn't take much. CarInsurance.com offers a "What's Your Limit?" online calculator, with the caveat that you should "err on the side of caution" when guesstimating impairment.

I don't drink, but if I did I wouldn't rely even on a portable Breathalyzer. Instead, I'd ask someone for a ride or call a taxi. (Some bars will pay for the cab.)

Whether you're pub-crawling, celebrating at a friend's home or hosting a party at your own place, make sure no one gets behind the wheel if he's impaired. Call a cab or let the tiddly one sack out on the couch -- that way, you get to wake him the next morning by shouting, "Erin go home!"

P.S. Don't forget to factor in the cost to your reputation once those iPhone pictures start making the rounds. You know, the ones taken after your fifth beer, when you're wearing a giant green hat and attempting an Irish jig. Friends don't let friends do the Riverdance.

More on MSN Money:

• Buy your own Breathalyzer
• 8 cheap, extraordinary entertainments
• Frugal game-day snacks
• Drivers OK with in-car Breathalyzer