Does America sell RPGs or Grenade Launchers or land mines/IEDs??

Yes they do. You need to have a squeky clean background however and a special license (usually historic military preservation people are only going to get such permissions legally) but under the national fire arms act a eligible u.s. citizen may posses a "destructive weapon" providing he/she can pass a FBI/BATF background check and pay a $200.00 license fee.

It depends if the GREED in their hands kicks in.

No.