Dan has it right. With our (currently) state owe liquor system, there isn't anything as one store that is cheaper than another.
People commonly think that when they start up their home bar they need to stock it up with enough different types of booze that they can make a wide variety of drinks. There are a few problems with this approach however.
First off, it is EXPENSIVE! When faced with a long list of booze to buy, and after seeing the prices of the "good stuff" the tendency is to go with the cheaper products, which will result in making cheap tasting drinks.
The second problem, is that you probably don't know how to make enough drinks to actually utilize all of those things on your shopping list. If you happen to have some random wad-o-drinks book around, you might fumble through some pages looking for something that uses that Blue Curacao that somebody said you needed to have, and then slop the ingredients together and up with a rather dismal drink.
Here's my recommendation, and how I got started (after a few "false starts" with the shopping list approach).
1. Decide upon a drink which you know you like (something common enough that you can order it at most bars).
2. Collect a few different recipes for it, hopefully from reputable sources.
3. Make up a shopping list of what you need for just that one drink.
4. Mix that drink, and that drink only, for a week or two. Try the different recipes you found. Play around with proportions a little until you figure out exactly how you like it. Write that recipe down!
Now that you have this drink nailed, go back to #1 and start all over again with a different drink.
Using this process, over the course of a couple months you'll gradually (and affordably) build up a very nice home bar, which only contains products you'll use AND you know a great drink to make with each product.