A Half Price Card is a discount card you can buy which allows you to only pay half fare (children's fare) for all transport in Switzerland.
It costs CHF 120 for 1 month. Details here: https://www.sbb.ch/en/leisure-holidays/travel-in-switzerland/international-guests/swiss-halffare-card.html
If your total transport costs in Switzerland exceed CHF 240, it would pay off to get a Half Fare Card.
You can look up fares on the SBB website: https://www.sbb.ch/en/
Your prices confuse me, because you use $. Switzerland uses the Frank (CHF), and that is what SBB prices are in. I have no idea what sort of '$' you mean or where you got these prices from.
I quoted you the prices for some of your trips in my previous post:
Vevey to Rougemont costs CHF 26 full price, Zürich Flughafen (airport) to Vevey costs CHF 79, Vevey to Lausanne costs CHF 11.20.
A Swiss Travel Pass costs (2nd class): 3 days CHF 225, 4 days CHF 270, 8 days CHF 398, 15 days CHF 485
Details here: https://www.sbb.ch/en/leisure-holidays/travel-in-switzerland/international-guests/swiss-travel-pass.html
P.S. Lausanne to Geneva takes 36 minutes and costs CHF 23 full fare, 2nd class (CHF 11.50 if you have a Half Price Card). All these prices are from the SBB website, and are what you pay when you buy at the station on the day. There are rarely discounts for advance purchase.