My wife and I are going to get a divorce soon but there are kids involved. I have tried numerous times to make the relationship work but I can't do it alone. I recently filed for custody of the kids as she in my opinion is neglectful of them. We now live with my mother and my wife just stays in the room on the cell phone and computer all day while the kids are home. School has just started and instead of taking the kids school shopping she went to Las Vegas to see her mother. She makes very bad decisions when it comes to money which is the reason we are in my mothers house and have yet to get out of it. Our daughter needs eye and dental work and my wife has been spending money badly all year. Tax time she took the money and bought rims and an alarm system to put on her car. When the stimulus check came she took a trip to see some of her relatives. Now she just finished up a trip to Las Vegas. We have two kids together and four in the household total. Whatever the kids need me or my mother provides it. Now my wife wants me to be nice about the custody and let our daughter stay with her even though she really doesn't spend time with her. I am afraid if I do she will know that she can always call me for money when she has blown hers and my daughter may not get the attention or necessities she needs. Our daughter is 4 and her brother is 5 and have always been together and I really do not want to split them up. I can take care of them financially also. Should I reconsider the custody or go through with it. We are splitting up over things she has done but instead of being mad I just want what is best for the kids. I am not trying to keep her away from them I just want them in a stable environment.

If she takes your daughter then you will have to pay child support to her and if she is not good with money, then you probably know where that will go!

NO WAY. You are in the right, she has proven her inability to care correctly for those children. Its your duty as their dad to protect them. This isn't about being "fair" or worrying about hurting her feelings. You need to do what is best for the kids, no matter what.
I would continue to file for custody, with her background (and your mothers testimony/statement, as well proof of her abusing money when medical needs have to be met) as well as you being more financially stable, the court is quite likely to grant you full custody and provide her with supervision.