To get unlimited Caps and supplies, you will need around 3,000 caps and two of the same weapon; one weapon in very good condition and the other in bad condition. Go to the merchant and purchase everything desired. Then, sell the merchant both of the weaopns. Buy back the cheap one and then sell it back. The merchant will give you the weapon in good condition every other time that you sell it and buy back the cheap one. You can now sell it back to the merchant for 3x what you bought it for. Repeat this until you have all you Caps back and everything that the merchant owns.