One of our favorite glitches in Fallout 3 was the glitch to obtain a very large amount of bottle caps from a vendor in towns. Thankfully this glitch is back in New Vegas!

1. Go to any trader.
2. Look for a weapon that has two quantities but different price.
3. If there is only one weapon that you can find and you have an extra in your inventory, sell it and the price will change when the trader owns it.
4. Buy the cheapest weapon of the two
5. Sell it to the trader
6. Buy it from the trader
7. When you sell it this time, the amount of caps that the vendor will buy will be doubled depending on the weapon.
8. Repeat the process...
9. Enjoy your spending spree!