Let me try this again for you:
You have armor worth $17000.00
You want to sell it.
Go to Creeper, begin dialogue
He has $5000 to spend on items...not enough
You MUST have at least $12,000 to buy items from him to equal his having the amount for the armor.
Buy items worth the $12,000 you need him to have
You buy and have the items, Creeper now has $17,000
(His original $5000+the $12000.00 you just gave him for items you purchased from him).
Sell him the armor worth $17,000.
You have sold him the armor, he has the armor and 0.00 money. You have the $17000 for the armor
Touch your keyboard key T and slide the slider to reach 24 hours.
Creeper has $5000.00.
You have items you purchased from him that you do not want. Sell them back to him up to his $5000
Each time he cannot buy anymore from you.
Press the keyboard key T, slide 24 hours.
He has $5000 each 24 hours period.
I always made sure I would buy items under the $5000 mark so I would not have to repeat his having to sell me to in order for him to have more than $5000.
Does that help??
You would have to do the same for the Mudcrab-only his amount is $10000.00, but he is harder to find and so out of the way...