I am staying at the Flamingo in March, I know there is a shop behind Bill's, I have never been to the store, not sure of the name, looking for different micro brews
It's called the Stage Door and they have a pretty good beer selection there. I bought a 6-pack of Fat Tire for a buddy of mine who wanted it for a Limo ride. They also have a small lounge in front.
Tip for the Stage Door: make sure your vaccinations are up to date. If you are willing to take the shuttle from Bill's to the Gold Coast, they have a liquor store inside with really good prices and discounts for Coast (B Connected) cardholders.
Gold Coast's liquor store is actually more of a gift shop with a liquor section. The Orleans has a dedicated liquor store with a much larger selection and the same prices....I'd suggest catching a shuttle there instead.
Both are run by Boyd Gaming, and yes, the prices are better than the grocery store. Their director told me years ago that they tried to beat "Lee's Discount Liquor" prices on all their items - and Lee's is usually significantly cheaper than grocery stores.