This takes a considerable time as it requires you to sell to a trader. They quickly run out bottle caps, and only respawn with more bottle caps after FOUR days, so it is slow. If you have opened up the game quite a bit, then I suggest going to different traders in one go to speed up the process.
The aim of this glitch is to sell a broken item to a trader, then buy it back repaired and then re-sell back the repaired item, to the trader for a profit. The trader repairs the item for free, so it is a win-win trade for you.
For this glitch to work you must have only ONE of the SAME item as the trader. For example, you have ONE Laser Pistol, the trader has ONE Laser Pistol. You cannot walk in to the shop with two laser pistols, or it will not work. For the purpose of demonstrating this glitch, I suggest you empty your whole inventory into a locker and have only a Laser Pistol. This item seems to work quite well, but it does work on other items. Also it seems all traders have Laser Pistols.
The item does not have to be the same condition and in fact, the more broken, the bigger the profit.
Go to a trader and trade with them.
Make sure the trader has the SAME item you are going to sell.
Sell your item to the trader.
The trader should now have two of the SAME item.
Now buy back the CHEAPER item.
Nothing happens the first time and you should have back a BROKEN item.
Sell it back again to the trader.
Now again, buy back the CHEAPER item.
When you buy it back THIS TIME, the item you will notice is FULLY REPAIRED and at a higher price. If it is not fully repaired (or just partial) just continue selling and buying back.
When the trader becomes broke, wait FOUR days, then return and repeat.
Money Glitch Two
This requires doing the Stealing Independence quest and Reilly's Rangers quest. The glitch allows you to obtain a special SMG (that is worth 430 bottle caps) many times over, so you can sell it. You must do the quest and not let your accomplice, Sydney, die. Obtain a Holotape from her dad's corpse from the Statesman Hotel (on Reilly's Rangers quest), then return and give it to her. She will give you a SMG every time you select the conversation. The Stealing Independence quest starts at Rivet City when you talk to the old man at the American museum near the market. Visit the National History Museum to start Reilly's Rangers quest.
Again, this is time consuming as not every trader has more than 430 bottle caps to buy the SMG. I have posted a video below from YouTube of the glitch. Credit goes to vmatt1203 for the video.
Glitches That Unlock Achievements 