As the sign at the Metrodome declared, "We like it here." And that affection applies to shopping, as Twin Citians tend to be quite loyal to locally owned businesses.

But over the past two decades, three national discount outlets — Sam's Club, Costco and Trader Joe's — have planted roots here and gained avid followings for their value-priced groceries and other items.

Including wine.

For some of us, especially wine.

The three chains, which have several locations in the metro area, differ greatly in inventory and approach, but they all permit us either to do some Champagne living on a swill budget, or just to save some serious dollars on favorite brands.

Costco, for example, cuts great deals on national and state levels and stays well below the usual retail markup. Trader Joe's has a slew of exclusive brands at low-low prices, making exploring cheap and easy. Sam's Club focuses almost entirely on familiar brands that fit its big-box image — though most come in bottles, not boxes.

Small wonder, then, that Costco and Trader Joe's are No. 1 and No. 2 in U.S. retail wine sales, with Whole Foods, which will sell wine at stores opening this year in Maple Grove and downtown Minneapolis, ranking fourth.

How do they do it? We visited branches of all three in the western suburbs to find out. For a closer look at the service and selection, the quantity and quality, turn to Page T4.

Costco

The space: Just like the rest of the store: nice, wide aisles

The service: Preoccupied but professional when engaged

The selection: A constantly changing array of wines at all price points, including a lot of acclaimed $20-plus wines from all over the world; easily the best high-end outlet

Target customer: People looking for value at all prices and for the occasional gem

Other libations: A good bit of beer and spirits, standard brands and some higher-end

House brands/exclusives: The Kirkland wines usually are good-to-stellar but often not around for long.

The actual wines: The Kirkland Signature Champagne ($20) and Columbia Red Blend ($19) were solid efforts, the Kirkland Pinot Grigio ($7) a screamin' bargain. If and when the Old Vine Zin or Cava are around, grab them. Costco often has limited amounts of highly rated surprises (half-bottles of Chateau d'Yquem for $99) that make it a potential gold mine for wine geeks.

Sam's Club

The space: Cavernous; inventory is poorly organized

The service: Sparse but quite cordial

The selection: A wealth of familiar brands from the lower price spectrums (Blackstone, Cook's, Ménage à Trois), with a few oddities (Chianti with a straw covering!)

Target customer: People looking for familiar brands at rock-bottom prices

Other libations: Virtually all of the usual suspects and a few more exotic choices

House brands/exclusives: None

The actual wines: In trying to find something distinctive, I sampled Newman's Own California Cabernet Sauvignon ($9), Sockeye Central Valley (Chile) Pinot Noir ($11), the Bottaro Chianti ($8.50) and the Cantina Zaccagnini Pinot Gris ($12). All were drinkable but just barely. This is probably not a great outpost for the adventurous wine drinker.

Trader Joe's

The space: Compact; inventory is well-organized

The service: Engaged, enthusiastic and knowledgeable

The selection: Often-unfamiliar brands with "cool" labels, plus a boatload of Charles Shaw/Two- (actually Three-) Buck Chuck; bonus points for carrying local stuff (WineHaven)

Target customer: People who are adventurous but very value-oriented

Other libations: Limited supply, mostly value-level but well-chosen

House brands/exclusives: Exclusives are labeled, often cryptically except for Trader Joe's brands

The actual wines: A $10 Barbaresco (from exclusive brand Rocca dell'Olmo)? Believe it, and enjoy its soft, barbera-like goodness. The Black Mountain Pinot Noir ($7) and Trader Joe's Coastal Zin ($5) were simple and consumer-friendly. The Trader Joe's California Reserve Sauvignon Blanc ($6) was a buy-it-by-the-case fabulous find; the Villa Alena Moscato ($8) delicious.