I think it is very important to get good imported cheese (aged over 90 days, which most imported swiss is) rather than regular cheese. I usually use about half Swiss half Gruyere (which is another type of Swiss). Usually the gruyure is more expensive, I’m
not sure you have to use it, but I usually do. The best deal on these cheeses, that I’ve found, is either at Trader Joe’s or Costco. I have never looked at Sams, but they might have it, who knows?. You can expect the Swiss to be about $6/lb and the Gruyere to be about $10 (expensive I know, but worth it!) At a regular grocery store it is usually even more expensive.