>>105657332 (OP)Broadcasting AM is pretty much dead.
Power inefficient as opposed to single side band or FM.
AKA very expensive to push signals far,
To broadcast anything in the ether you will need a license and some know how.
You risk getting you shit pushed in by the FCC or you nations equivalent (and every century has an equivalent) or the ITU.
The fines are huge.
Broadcasting in a reserved part of the spectrum can also risk interfering with "reserved" parts of the spectrum. And this will get you V&, your gear confiscated and a felony charge.
In terms of "broadcasting" getting a HAM license wont allow you to broadcast anything "fun" like music news etc. You're pretty much stuck doing contacts across the world. The exact rules very place to place but it's reasonably cheat. You can get a license for less then 100$, and a station shouldn't set you back more then 200-300$. You can also make one if you have to know how or buy a Chinese QRP(low power) station for 25-50$ that's good enough for CW(telegraphy)
You will also need a considerable amount of space for an antenna. You can make a diploe with nothing more then 20m of wire, but you will need to trim it to size and match the impedance.
You can get a national commercial broadcasting license. Since AM radio is pretty dead, the license itself isn't that expensive anymore maybe 1000-5000$ depending on the state, region, and regulations. Essentially, once a year an auction is held for parts of the spectrum. Most AM radio frequencies are operated by religions groups, and may parts of the spectrum are vacant.
That said your station will need to pass an inspection, and have gear that's committal grade and certified and depending on you know how, connections etc, this will set you back a pretty penny. Although i dont have an exact number i can tell you that 1h of a certified labs time will run you 5k and upward. And it will take many hours to certify your station.
If you have any questions, ill stick around a bit more.