The Coca-cola example does not work with large amounts of money. You can only then launder up to a 1:1 ratio of illegal client money for your legitimate customer money. That would require a lot of legitimate customers. Larger amounts of money require receipts, taxiing, and cost justification. Why would a legitimate customer pay twice the going rate for a product?
If you were all three parties (buyer, seller, and wholesale supplier), you could make it work. It would be very risky. The chances of looking suspicious and getting caught would go up exponentially to the amount of cash being transacted.
Another way would be to sell the item twice as a sort of straw purchase. If the seller and wholesaler are the same party, the seller could buy the product from the wholesaler at an inflated price. The buyer would then buy the item for a reasonable price. The seller would then be losing money. But, who cares. The only way to cover the difference in price would be to inject the illegal money of the client into the cash flow of the seller, mixing it with the legal money of the buyer. The money coming to the wholesaler would be clean although tainted. At least, it would be receiptable. Only the seller part of the operation would be at risk. Only if they hide the loss by receipting the buyer at a higher price.
Another take on the above scenario would be for the seller and the buyer to be the same party. Again, the product would be overpriced. But, the product would have to be something that could be very price flexible. Or, something that would require a contracted price due to uniqueness or difficulty in obtaining. This could be anything from art to industrial equipment. Just as long as there is clean cash from somewhere to mix with the dirty cash.
The least risky scenario would be to engage in a cash business with few to no receipts and no hard assets being transacted. Vice businesses like strip clubs and casinos are perfect for this. Dirty cash from the client can be injected into the business labeled as clean cash from the customers. If it is a business that typically sees a lot of large legitimate cash transactions. It would be harder to detect and track the mixing of clean and dirty money. This especially works when paying out more to the customers (in this case, gambling winners) more than you are taking in revenue from their business.
During the run of the show, Marty and family engage in a little of each of these schemes. An example of this is Marty buying all of the struggling businesses with cartel money. Then, all of the revenue from the businesses were transferred to the cartel at a loss. The loss was the cost of doing business to convert the illegal money into seemingly legitimate money.
Another way of doing this is to use a legitimized business like a bank to give the tainted money the air of legitimacy. For example, if Marty were to get a bank loan for a business, he could then pay back the mortgage or business loan with cartel money. It would not matter if the business made a profit or not.
Typically, the US government puts the onus on the seller and/or the lender to know and vet their clients/buyers. You are supposed to vet any cash or cash equivalent coming into or being put into circulation through a financial institution licensed by the federal government. Since vetting every small transaction would be too tedious, time consuming, and cost prohibitive, the federal government puts a cap of $10,000 on transactions needing scrutiny. The federal government also stipulates that transactions, spread out over time that have the appearance of trying to circumvent the cap, are also to be scrutinized.
Illegal operations buy property and businesses using cash and loans. They get either unscrupulous middlemen or lenders who themselves have clean reputations to handle the transactions. These “straw purchases” are still illegal. But, now the cash has the air of legitimacy.