Ok!

(Every penny you have? Not sure if I should take that seriously, but since it's not what I'm suggesting, I won't linger long on it)
So... Excessive gun control will cost a lot of money as well...not as much, to be sure, but a lot.
Since the money is coming out of your pocket now, where would you like to see it spent? Gun control only impacts those who were never a problem to begin with: people willing to obey the law. Given that you have 300 000 000 guns already in circulation in your country, criminals will have more than enough access to guns, which they would posses and use illegally - if they are willing to now, they will be willing to immediately after any new laws are passed. Also, you're going to create an even great rift between pro and anti gun folks. It might cost less, but I wonder what you're actually buying.
Fixing root cause, however, will impact the folks more that were the ones you had to worry about: the poor, the mentally ill, the disillusioned. It will get them the help they need, and give them options other than violence and crime to reach a level of success they feel they'd like to. They'll be more like you and me - thinking about the weekend with their children or planning what they would like to do with the back garden or where what movie they'd like to see with their significant other, vs. robbing a store or killing a competing gang member, or taking out a school. Also, the pro gun crowd won't be up in arms (ahem, excuse the pun) over having their constitutional rights taken away, so there's likely to be buy in from their side as well. Plus, you'll have all the other side benefits of having a happy, healthy citizenry.
So...without having the specifics, the cost analysis, the policy manual, but only the description as I've laid it out above, if you could only pick one, which do you like better?