Each week, we bring you our top picks for the best places to booze on the cheap in SF.

1. Drink Me's South of the Border Party: The good folks over at Drink Me magazine are throwing another of their cheap-booze parties; this edition, held at Tres Agaves, has little choice but to be Mexican-themed. Join in a free tequila tasting, sip on $4 cocktails and $3 beers, and nosh on the free taco bar (for the first hour only). Whatever you do, though, be sure to RSVP before you go-- otherwise, it's a $5 cover. (Tuesday, September 28, 6:30-10:30 pm, at Tres Agaves, 130 Townsend St., SOMA.)

2. Cocktail Week Pisco Sours: In honor of SF Cocktail Week, Pisco Latin Lounge is serving up $6 doses of its titular spirit, in the form of a pisco sour. Feeling peckish? You can also use this little coupon to get two-for-one apps at Pisco all this week. (Thursday, September 23, 5:30 pm-12 am, at Pisco Latin Lounge, 1817 Market St., Upper Market.)

3. Dinner and a Drink at MO Bar: Unless they're in search of one-night stands with Midwestern businessmen, it can be hard to convince any SF native to hang out in a hotel bar. That said, the Mandarin Oriental is doing its best to make a compelling case, with a dinner-and-drink happy hour that pairs a simple meal with a glass of wine or cocktail for $20. Snag a burger and a Cab, or Singapore noodles and a pear martini. Don't need as much sustenance? Order a plate of sushi Monday-Friday, and get any glass of biodynamic/organic/sustainable wine for half-off. (Dinner and a Drink: Monday-Friday, 7-10 pm; Sushi Happy Hour: Monday-Friday, 6-7 pm, at MO Bar at the Mandarin Oriental, 222 Sansome St., Financial District.)

4. Win Cheap Drinks with SCVNGR: As the phone-app world continues to expand, it seems inevitable that the next step will involve merging iPhones with inexpensive booze (though hopefully not literally, unless having Steve Jobs put a price on your head is your thing). Enter SCVNGR, whose mixture of check-in service and contest allows you to score cheap drinks at spots around the city, including the Blue Light, the Brick Yard, Triptych, and Nova. Download it now, and let the adventure begin.

5. Half-Price Wine at Royal Exchange: If you're a workaday type finding that humpday gets you really, really down, consider a trip to the FiDi's Royal Exchange, which is currently offering select bottles of vino for 50% off on Wednesdays. Drink bottle, watch baseball, have unproductive Thursday, feel better. (Wednesdays, 8-11 pm, at Royal Exchange, 301 Sacramento St., Financial District.)