First of all sorry for my english.
Me and my little brother used to love play a map called one room (cod waw). We always thought about adding buyable ammo to this map but I have no idea how to do that. I watched videos about but I couldnt do it. Doctors told us my little borther is Leukamia. I want to give him a gift and make him happy.A gift that he always wanted. Can anybody help me about it. 

Sorry for disturbing you with my problems. Thanks for help

Map link:  
http://www.mediafire.com/file/sd7870pj82f2kie/OneRoom+Installation.exe