Whether you are looking to buy a cheap softball bat or a discount bat you should always consider your return on value. I often tell people that you can buy a bat for $300 dollars that you will feel confident with and is forgiving when you mishit it but you if you decide to go the cheap route and buy $100 bat you will not be as fortunate. In sports equipment does make a difference. Even if it is simply a mental advantage.
There are a few things to consider when picking out the right bat. The first is what is legal for the league you are playing in. ASA, USSSA, NSA, SNA etc. Even local community leagues might specify ASA bats but ban a few of them due to known performance, to protect the safety of the players.
The second consideration is the weight. Most slow pitch bats are 34 inches in length but the primary weights are 26, 27, 28 ounces. Along with the weights softball bats also have different weight distributions. Some are balanced and some are end loaded. Pick up the bats and swing them to see what you prefer. Generally power hitters swing end loaded bats and base hitters swing balanced.
Lastly check out the reviews online to see what other players who have actually used the bat have to say. Usually ratings are given on a large enough scale that the reviews can be considered worthwhile in making your decision. Buying a softball bat is a big investment but it sure can add a lot of fun to the game when you choose the right one for your game.