Fresh water fish keeping is actually pretty damn easy. Do a little homework on the fish you want to keep and stay on the ball with tank husbandry. I mean really come on; all a responsible fish keeper has to do is read and follow some pretty simple directions. Put in a few hours of reading towards something that is going to be in your house for years.
After you know what fish you want, buy an appropriate sized aquarium and filtration system, cycle your tank and go from there.
For the Oscar's sake I hope that this is really just a joke/troll thread. If not, then I suggest taking the fish back to the store and putting your tank away until you feel like you are responsible enough to do a little homework.
This isn't rocket science.