Im at the point where I have no ammo. Ive spoken to somebody whos got guns and ammo for sale. In order to increase my caps to buy I off load some stuff to him and then with the caps begin to buy. The problem is when Ive completed the transaction the guns or ammo do not appear to have been credited to me. When I go back and talk to him he still has the stuff I sold him plus the stuff I thought Id bought. Any ideas, I know its just me being thick as Im still not used to this game but Im out of ideas.

Hmm. There is something you're not doing right.. or at least.. i think.

You gotta give more details on what is happening. What buttons do you push, How many caps do you have to begin with, etc... It sounds like you're just not actually buying the stuff you think you are.

As this is the spoilers section I guess I can say that Im speaking to Cliff Briscoe. I press A to talk and then click on the "what have you got for sale speech". The screen comes up with items, top left says 96 caps and top right 532 caps. I press on the hot keys button and it takes me through weapons, aid, apparel, Cliff Briscoe etc. For example I click on 357 Magnum Revolver which has in brackets 2 and then the number 36, press a and then x to accept. Actually this time it has worked but other times Ive lost caps and not got weapons or ammo. Maybe theres a bug or Im doing things wrong sometimes. Im still getting used to how it works. Thanks

You need to make certain the big green arrow between the two columns with the number in the middle stays lit up and green. If the arrow/number gets dark, then you either don't have enough funds/credit or the NPC cannot afford the transaction.