Any "RM" or Recoltant Manipulant "Grower Champagne" you can get your hands on. And all of them including some vintages pretty much are under $50. These are all single estates that grow their own grapes and aritisanaly produce Champagne. This is in contrast to the "NM" or Negociant Manipulant coded Champagnes that are made by all the big champagne houses and big names we know, who buy their grapes from large groups of farmers and produce wine in very large quantities. There are also: CM cooperative de manipulation, a wine made by a cooperative of growers, I've never had a good one RC recoltant-cooperateur, a wine made by a grower who produces Champagne with the help of a cooperative, I've never seen one in the US MA marque d'acheteur, when the brand is owned by a third party who is not a producer - always complete shit. RM's are the most underappreciated and most amazing values in Champagne today. If you can find any in a wine store, buy them. If you want to throw in the odd American wine for the wine tasting, get the Argyle 1998 Brut ($15) or the Argyle Extended Tirage (about 30-40 dollars a bottle if you can even find it or order it). Their Rose ' is also supposed to be magnificent. The best sparkling wines made in the US, no question.