It can be difficult to make a homemade beer that tastes exactly like a particular commercial beer, like Costco's Bud Light. Commercial breweries frequently have access to specialized machinery, certain ingredients, and extensive production techniques that homebrewers might not. Large breweries like Anheuser-Busch, the maker of Bud Light, also often keep their precise recipes and brewing techniques as trade secrets.

However, you can try brewing a light beer that resembles Bud Light in some ways. The following is a general instruction on how to make light lager at home:

**Ingredients**:

- 5 to 6 pounds of pilsner malt or light malt extract - half a pound of maize sugar (dextrose)

- Mildly bittering hops (such as Saaz and Hallertau).

- Addition of optional aroma hops (such Saaz or Tettnanger) to give the beer a faint flowery or spicy scent.

- Lager yeast that fits the genre

- Setting up sugar to carbonate

**Equipment**: a siphoning apparatus, a large kettle for boiling the wort, a glass carboy or bucket made of food-grade plastic, and a fermenter.

- Packaging supplies like bottles or kegging equipment

**Instructions**:

1. In the pot, heat up around 2-3 liters of water. Remove from fire after it is heated, then stir in the malt extract or broken pilsner malt. Stir thoroughly to dissolve.

2. Once the mixture has reached a rolling boil, add the bittering hops. According to the hop schedule based on the alpha acids of the hops you select, boil for 45 to 1 hour.

3. If you want some hop scent in your beer, add the optional aroma hops during the final 10 minutes of the boil.

4. Immediately after boiling, use a wort chiller or submerge the kettle in an ice bath to quickly cool the wort to about 70°F (21°C).

5. Add cool, clean water to the fermenter to fill it up to the required batch capacity, which is normally 5 gallons, and then transfer the cooled wort there.

6. Place the airlock on the fermenter and add the lager yeast.

7. Use a controlled temperature for the yeast strain you choose to ferment the beer. It would normally be in the range of 45-55°F (7-13°C) for a light lager.

8. Once the fermentation process is finished (which could take many weeks), bottle the beer and add priming sugar or carbonate it in a keg with CO2.

Please keep in mind that this is only a basic overview and that there are numerous subtleties in beer brewing that might impact the final flavor. A commercial beer's flavor profile, such as that of Bud Light, may also include adjuncts, changes to the water's chemistry, and particular yeast strains that could be difficult to reproduce on a small scale. You can get closer to the flavor you want by experimenting with various recipes and cooking methods.

To prevent contamination and preserve a sterile brewing environment, don't forget to completely sterilize all equipment. Cheers to that!