Vary by jurisdiction. We tend to answers from all over the world, and can't even begin to make statements on this without knowing what jurisdiction you're in.
a purchase without planning and budgeting its naancense purchaseing
In the entire U.S. there are an estimated 20,000 or more gun laws.
No matter WHERE you use a gun, there are laws that govern what you can and cannot do. If you do not know those laws, please do not own a gun.
Your question is an incorrect statement. Why do you think states must not enforce gun laws? They do.
That is too broad of a question to answer as asked. Is there some specific information you want about gun laws?
Literally, tens if not hundreds of thousands of laws. My copy of US state gun laws is about 2 inches thick. It is estimated that there are more than 20,000 gun laws in the US- and you are asking about "around the world".
Like most states, there are far too many gun laws for a brief answer here on Answers.com. However, this is a link to a review of several of their gun laws. https://en.wikipedia.org/wiki/Gun_laws_in_Louisiana
barak obama is pushing for more vigurous gun control laws and background checks
NRA members vote against gun control laws.
What country?
Owning a gun is not illegal if you follow the laws.
The first layer is federal gun laws. From there State laws can restrict gun laws more, but not make them more liberal. From there County laws/ordinances can restrict more so, but not make them more liberal. <><><> Above is correct, but with an exception- Many states have enacted "preemption" statutes, to prevent a "patchwork quilt" of gun laws that vary dramatically city to city, county to county. In those states, the State Legislature preempts the ability of a county to pass gun laws, reserving that right to itself.