Costa Rica is not the cheapest country, and Monteverde / Santa Elena is not the cheapest town, but I have been learning some important things from the locals here. Like where to drink. ;) Here are some great places to grab a drink while you're here.
I'll start with the non-budget places first. Some happy hours offer free or cheap bocas (tapas) so keep an eye out for that. Grab a bite to eat before you go out (see Best Places to Eat Around Monteverde). Trust me, you're going to need food if you want to go out and dink Tico style. ;) See Those Ticos Can (and Do) Drink!.
Tap House
You'll feel like you're in any modern bar in California with it's simple cinder block and cement motif, tap beer, and (sometimes) live music. It's downstairs from The Open Kitchen, next to the Jiménez Bakery at the northern tip of the triangle. They serve food from the upstairs restaurant and have daily drink specials, usually around C3,000 - C4,000.
You can get anything from fancy crafted cocktails, to chili beer on tap, to the local Imperial or Cacique. Prices are mediocre but not bad for the type of place it is. If you want a quick bite, you can get a nice bowl of edamame for only C1,500. Five stars for Emel the bartender!
UPDATE March 2021: Still closed due to COVID.
Celajes Lounge at Hotel Belmar
The Hotel Belmar is a fancy resort and has a lounge with their own microbrewery and an incredible view all the way to the Pacific Ocean and signature garden to glass cocktails. As you can imagine, it's pretty expensive BUT they have a somewhat non-impressive happy hour that they call Tico Time (1/2 price house wine and bottled beer, free bocas with a regular drink).
Go there for some snacks or a beer and to watch the sunset. It's amazing. It's on the road to the cloud forest and up the hill to the left at the trail to Cerro Amigos (the hike up to the radio towers). See Best Places to Eat Around Monteverde for their menu.
UPDATE March 2021: They have now opened a tap room down by the pond where you can sample their craft beers.
Selina Hostel
Also super hip and trendy. Selina is the WalMart of hostels. They have locations all over the world including one near the Monteverde Cloud Forest Reserve. They have the model down pat and attract a lot of recording artists. The neighbors don't really like the place because of the light and noise pollution it puts out so make your own decision on if you want to give them your patronage. Walk past the giant wooden lounging man sculpture in the parking lot into the full bar where they have a lot of live music and DJs. Drink prices $6 for a gin & tonic.
Bar Amigos
A big disco in the heart of town that has pool tables downstairs. It's where you go if you want to go dancing and hang out with locals and tourists alike, and they have what I consider to be the best chili guaro shot in town. It's down a small offshoot in the triangle. They have a DJ every night and live music on Fridays that usually entails a cover charge. They have a full menu with reasonable prices and it's also where you can buy cigarettes after all the shops are closed! See Best Places to Eat Around Monteverde for their menu.
Pura Vida
I love this small simple local's place with a view to die for. They have a full bar and fantastic, reasonably priced bocas including the best patacones I've had so far. They have free bocas until 9pm and you might even see Capuchin monkeys while you're there! It's on the road leaving town to the south.
UPDATE March 2021: The place is now called Marisquería y Restaurante Manolo's. It looks pretty much the same.
Varvilla
You might get some looks walking into this place if you're a gringo. I was fortunate enough to be traveling long term and hanging out with some locals so they were my cover here. ha ha. There's no tourist fluff here; just a straight up local bar with bocas for C600 (ceviche, fried rolled cheese tacos, etc.). It's just off the south east tip of the triangle.