ask them to cut you on prices and try to get all three to go for about what you are paying for one... or get to go to half. that way you get twice as much pot for the same amount of money and two of them are happy... I'm sure if one's giving you an 1/8 for every two, getting it down isn't too hard...

or what i would do... smoke twice as much pot, then you'll take care of more people... i don't see how having too many people wanting to sell you pot is a problem