I'll amplify a little on what JA said: What's the recipe? There are reasons to use sugar in your beer, if for example, you want less malt flavor - yes, sometimes that's a thing - or if you want the beer's body thinner. Without additional information, there's no way to know how to recommend. As to the sugar, brewer's crystals, cane sugar, beet sugar, table sugar, they're all the same, sucrose. Use the cheapest version you can find (bargain brand table sugar at your supermarket).