Remember the time it was confirmed that Booster is easily able to hack into government files because computer systems today are so primitive to him?
This was also in the Flashpoint world during a time of war meaning far more security existed. Just think what that means about his character. He could easily have gotten rich by other less heroic means and it's likely he could have done it without getting caught. Ted didn't even know Booster could do this in CTIC and if he was able to use the computer he could have found Max.
He's also kept this ability a secret from others but why? I have a few theories on this but first and foremost Booster is actually pretty tight lipped about himself. Trixie noticed this right away, despite him always addressing the press he doesn't reveal much. Yes part of that had to do with his origins but I always saw that as him having trouble opening up in some respects. There's stuff he didn't even tell Ted and some that he tried to keep from Michelle.
Not letting the hacking skill be known could relate to a couple things. His image for one is based on the feats he does as a hero which are mostly physical. When Booster Gold first became a hero he never let anyone know his powers were even tech based. Skeets played a part of that as he knew it was never wise to let outsiders know too much. (*1) Booster himself is rarely seen messing with technical stuff. He either had someone telling him what to do (Skeets) or left it to some genius. (*2) Hacking and building things aren't the same though.
I think he'd also keep it secret because he knows people would blame him or suspect him of wrong doing. One of my favorite bits at the end of the Manhunters mess was Booster confronting the JLI and pointing out that they always expect the worst of him. As great as his friendship with Ted is I think part of him would know better than to inform him of this. (*3) Kooey Kooey Kooey was an example of Ted dragging Booster along for his crazy schemes. Ted was perfectly fine with stealing U.N. funds, roping in his gambling addicted friend and you remember what he wanted to do to get back their money? Rig the machines and Booster was against all of it.
Skeets wasn't around during this time so Booster would have had to decide not to do this. It would likely be tied to his dad's cons and wanting to keep himself from falling into the same pitfalls plus his desire to redeem himself/be a hero. One of Boosters' biggest problems was the inability to put his foot down. It happened with Ted and his dad. Because Booster wants to be accepted and be part of something. There's always been secrets that he's kept from others that can isolate him or cause him harm.
Back in CTIC Ted remarked how many heroes wonder how much Booster knows about the future. Most would think he'd use this to his advantage (granted he has but not as much as he could) and there seems to be a vibe of frustration. I could see heroes thinking he'd let something bad happen which would screw them over while letting him come out on top. Ted however notes that Booster still tried to take the hit meant to kill Superman.
I guess what I'm getting at is that Booster has reasons for not informing others. His restraint from babbling and not using such a skill for himself really tells you lot about him.
*1 Whether Skeets was trying to build up the whole "Greatest Hero you never heard of" persona is up for speculation. Sure it wasn't in mind when the original story was written but I wouldn't be surprised since Skeets was knowingly helping Booster achieve his destiny.
*2 Giffin and DeMatteis oddly seemed to attempt to imply Booster could do these things at least twice during their Booster Gold run. Jurgens has confirmed that Booster isn't at that level.
*3 While he does tell Ted in CTIC Ted doesn't know if he was being serious and Booster was willing to do this because he suspected Ted was in danger.