There are definitely ways to restrict what folks spend on and who they send money to. One of the easiest ways would be to set up a normal, non-interest earning

There are definitely ways to restrict what folks spend on and who they send money to. One of the easiest ways would be to set up a normal, non-interest earnings savings account with no cash on site. For personal use items, simply require they all come from the prison roster of stuff, and have a selection. Allow folks to send to limited family members: Parents, spouses, and domestic partners would get it if they lived together and had help from the person before the crime. Underage children could get it automatically (and probably should get it if the person had parental rights or child support to pay). Again, there would be no cash and reasonable limits on things from the commissary. Everything else can be saved so that folks have a good start when they get out. As far as bribing corrections officers: I'd honestly say part of the answer to this would be to train folks well (more than 2 months of training), pay them well enough to get good candidates, and make sure to keep the prison's well-staffed without relying on overtime. This is a hurdle, though, as most of the places will say they can't afford it.