In (Weeds) S04E05, Guillermo asks Nancy to write down a number of how much money she wants to make, and tells her to make it a huge number because you can only ask once, and so she does. This is to be her payment for working at the maternity store front. You don't see the number, but presumabley it is a lot.
Then, in S04E07, Nancy decides she needs to make some money and wants to start dealing again, at which point she approaches Guillermo and he refuses to sell her anything (except at $25 a gram, which is insane if you are buying 300 pounds). Guillermo continues the unfortunate trend of being a jerk towards Nancy (and no longer the likable character he once was) that he started when Nancy was caught looking into the tunnel.
So, my question is, what happened to Nancy's big payday? The whole point of running the maternity store front was to be the "white (blanca) face" of the Tres Seis gang, and in return she would be paid handsomely. So why did she need to start dealing again?