Wal-Mart sells several moscatos for less than $5 a bottle. It is hard to imagine you could find a good moscato at that price, but since the cost to try them was so minimal, I decided I didn't have much to lose. One of the low-cost moscatos they carry is made by Barefoot, which makes quite a range of inexpensive wines. Their moscato sells for about $5 a bottle and is actually a pretty decent-tasting wine (I easily could have finished the glass, which I can't say for a lot of wines), but the packaging alone would make me hesitant to buy it again. The bottles come without corks and are instead sealed with a metal cap that is extremely difficult to remove. It would be very easy to cut yourself on the sharp edges of this cap.
Oak Leaf makes a moscato that sells for less than $3 a bottle and it is not bad, either. It has a light, fruity taste that is very smooth.