It was 10 a.m. Friday morning, and I was on a mission from God.

Well, actually, I was on a mission from my editor. "Find me bargains," she said. "I need the cheapest buys, the biggest selection, and the best service around."

I knew what I had to do. I had eight hours until deadline to track down the best buys on Levis jeans, boxer shorts and Teva sandals in Harvard Square.

So I hit the street.

First stop: Serendipity on Mass Ave. Nice name and nice clothing, but no Levi's no boxers and no Tevas in sight. I exit.

Next door at J. August, my roving reporter's eye spots three styles of boxer shorts. They are cheap and not unpleasant. The best-looking pair sports a blue and green plaid design, a Harvard logo and lots of fuzzy flannel to keep you warm. The price: $16.

"It's the flannel that people want," says John C. Baestas, assistant manager. "That's one of our most popular items...usually with the young ladies. They sew up the hole and wear them as shorts."

Hoping for more than three makes of boxers, I visit Mass Army-Navy, farther down the street on Mass Ave. This place has an incomparable selection as well as good customer service. I am impressed.

The Tevas are downstairs, available in several different colors and a choice between firm and flexible soles ($45 and $55, respectively). While they sell well to summer shoppers, recent sales have been slow, says employee Jeff H. Thomas.

"During the summertime Tevas were a very hot item...People still occasionally come and ask for them," Thomas says.

Then he shows me the "Vintage Denim" or "Classic Rags"--euphemisms for second hand Levis. This "authentic recycled clothing" will set you back $17.99.

Upstairs, the selection grows even more immense. My fashion-curious eyes jump in glee around the two rooms, stuffed full with Levis upon Levis in every imaginable color, size and shape.

Classic rock accompanies my perambulation through this Levis heaven. I see upwards of 3,000 pairs in purple, red, two variations of olive green, twilight blue, hickory brown, teal, gold and the basic blues.

Jean styles include 501, 505, 512, 517, 519, 550 and Silver Tab for men; 501, 901, 512, 902 and 560 for women. Prices range from $24.99 for regular stone-washed to $40.00 for offbeat dyed colors.

"We have the largest selection and best prices," says Dave G. B., second floor supervisor of Mass Army-Navy.

They won't do you wrong in the boxer department, either. The store combines considerable originality with low costs: between $10.99 and $16.99.

Mass Army-Navy's best-seller is the Royal Stuart boxer, sported at one time by Scotland's royal Stuart family. (The tartan plaid, that is, not the boxers).

Numerous other styles include paisley, plaid and polka dot; athletic teams (Red Sox and Celtics); and cartoon heroes like the Tasmanian Devil, Opus, Rocky and Bullwinkle.

I proceed to the Coop, hard to miss in the heart of Harvard Square. The Coop corners the market on Jockey "Life" boxers. They cost $7.50 to $9.50 and are not pretty.

However, the copious supply of "sueded silk" boxers is impressive. Silk boxers cost $24.99--expensive but decorous. Flannel and Harvard boxers ($12) are also available.

On the Coop's third floor, I find a stacked wallful of Levis jeans. These jeans cost $36 to $45. The price may not be right, but smartly organized shelves make for easy shopping. Also, prices are reduced on occasion.

"The jeans go on sale pretty often," says Coop employee Tasha M. Tidwell.

During the Back to School Sale, for example, all styles (501, 505, 550, 560 and Silver Tab) cost $29.99.

"We're at an advantage because we have the Coop member card," Tidwell adds.

Next I visited fashion haven Urban Outfitters. This JFK St. store lures fashion-goers with its alternative, 50's retro-ambience and deconstructed furniture. But can it satisfy a student's need for quality, budget apparel?

Urban Outfitters carries only two styles of Levis (black and blue 501's, $44) and Silver Tab ($50). If you're looking for the Euro-alternative Girbauds, however, you're in the right place.

Boxers abound here as well, with a huge collection of cozy cotton and flannel-wear and brand names like Charles Goodnight, Calvin Klein and International News. Prices range from $13 to $20.

"People come here for variety, basically--the selection is great," says employee Lisa McGinnis.

In the store's "bargain basement" underworld for garments, I discover extensively used Levis for only $10.

Next: the Pennsylvania Company, across the street from Urban Outfitters on JFK St. This store carries lots of Levi's which are perpetually "on sale" for $28.99 to $36.99. Non-sale prices are $38 to $52, but the store accepts the Student Advantage Card for an additional 10 percent discount on sale prices.

Boxers fill two rows. The pride of the boxer collection is a glow-in-the-dark pair which warns "NO" in the light, then illuminates to "YES" in the dark.

Next stop: the Lodge on Brattle St. The Lodge has 501's, 550's and 560's for $42 and $44. But the Levi's are "on sale continuously," says employee L. Paul Robertson, usually running only $29.99 and $34.99.

"We sell really well to Europeans," says Robertson. "We've had foreigners periodically come in to try and buy all of our jeans."

But the real bargain here is the boxer shorts: the Lodge makes its own boxer-wear. All boxers are on sale for a 20 percent discount, with boxers left over from spring and summer marked down still further.

I reached the apex of my quest for Tevas at the Tannery on Brattle St. Inside, I was astounded by a large, plastic Greek-looking rock formation inscribed with the word "TEVA" and encircled by troughs of running water. Lodged in the rock are the numerous styles of Teva's "sport sandal."

The sandals cost $40 to $65, but students get a 20 percent discount.

My day's journey through the leviathan warehouses of Levis, boxer and Teva diversity reveals that, ultimately, the best bargain depends on the buyer. Given the incredible diversity of fashion in the Square, anything you might want is there for the buying.

Now that my mission is complete, maybe I can get on to my next assignment--where can a guy find a cheap bite to eat around here?