If you want it you can probably find it in Las Vegas. And if you have anything left after the tables or slot machines, or even if you hit it big, you might want to check out some of the unique shopping on the Strip and Downtown. The Strip especially is well known for some of the highest-end, most original shopping anywhere. Nearly every casino has at least one hall or even floor dedicated exclusively to shopping, from Via Bellagio's high-end merchandise, to the nearly endless boutiques within the Miracle Mile of Shops inside of Planet Hollywood.
Just south of the Strip but on Las Vegas Boulevard are the Outlet Malls and Town Center with more shopping for a bit less money than the shops at the Strip, and this will be found in the Strip shopping section.
And believe it or not, there are places off the Strip, and outside of Downtown. If you need groceries, a pharmacy, want to buy a six pack for less than $5/ beer, are thinking about saving some cash by making your food instead of ordering room service, or want a normal bar without insane prices, Vegas has all the normal stuff you'd find in any city and we'll help you find the right stores.
If you want to know what to shop for when you get to vegas then have a read of this What to Pack for Vegas guide.