‘Tubby Good Deals’ is a term given to an individual who in short, is tubby (or not so tubby) This term has nothing to do with good deals although it may be used in a transaction with tubby doing a good deal.
1.) good deal means awesome, cool, etc.
2.) good deal = drop it, when somebody is talking about something and you don't really care just say, "good deal, good deal" over and over again until they shut the fuck up.