Penny pinching jokes from Mr. Krabs or not, they only make like dollars a day at their frycook establishment. And Squidward is able to buy fancy and organic foods like imported cheese and etc. Both SpongeBob and Squidward seem always stocked with everything they need at home and have beautiful, if not expensive looking homes. How does this make sense? Well let's go back to the beginning for SpongeBob where he was looking for a home. Truth or Square to be exact. I believe that SpongeBob payed in front his entire wage for the home that he must have saved for quite a while. I mean just look at that money bag he had. Since the sale's lady didn't seem to enthusiastic when the finally reached the pineapple home for sale. And who would? It was just a pineapple that toppled off some fisherman's boat only moments later before SpongeBob and the lady arrived. Well that solves that. But what about Squidward? Even I'm kinda puzzled at this point about how he makes enough income.
Now let's talk about Plankton. He obviously doesn't make any money off his fast food. I think the clear answer is that Plankton made the Chum Bucket himself using his technology. Plankton usually doesn't eat meals besides his holographic meatloaf or many chum recipes (etc. Karen 2.0). So that solves the money for food issue. How's Plankton able to buy all the stuff he needs to make his invention though? Maybe a couple times a month he has a yard sale on his old inventions? We've seen this before in Move It Or Loose It. (But then again Plankton kinda makes it obvious that he hasn't done this before.)
Maybe I'm over analyzing Plankton's part of this money puzzle. I'm mainly curious about SB and Squidward though.