Just my opinion:
-Gambling: forget it. Just don't do it. OK, so you can gamble, but I strongly suggest you ONLY use dust from faucets (that you got for free). Math always wins, and math says that the house always wins. DONT gamble it is a fast way to lose your money. I only gamble for entertainment, not as a way to generate income.
-Buying: yes! There are some sites to check out. Coinbase lets you use ach transfer, other you can use a wire to move fiat around. Coinbase charges a 1% fee, other exchanges only charge their standard fee (usually ~.2%). So if you are moving a small amount of cash then coinbase is cheaper, but if you are moving more than maybe 6k or so, you might be better off with a wire. You need to do the math based on how much you want to move. Also, keep in mind that whatever exchange you use, you can move your bitcoins away from there in minutes, so if you don't like their features you can move the coin somewhere else that has better features for you. If you plan to not use the coins at all, I strongly suggest that you put them into storage, and DONT leave the coins in an online wallet. Things are pretty secure online, but best not to take the chance.
One more thing, if you are moving A LOT of bitcoins, like you are rich or something, you might want to look into a mixing service. Contrary to popular belief, bitcoins is not anonymous, and you can become a target if you have a crapton of money sitting in the same wallet. With a mixer you can divide into different wallets and it will be anonymous, and no hackers will know that you are sitting on a fortune.
-mining: the main thing here is cost of electricity. Where I live it is 20 cents kwh, so there is basically no way I can ever make money mining with the current technology, not even with undervolted modified stuff. Plus my electricity is tiered. But if you only pay 10 cents or less, you might be able to make money with mining. Most people will tell you not to bother, and if you are not willing to put in a lot of effort, I would agree. I think that mining for profit isn't very easy, so be prepared to work for it.
So welcome to the world of bitcoins, and good luck