The official base price for the annual Swiss Motorway Vignette (for 2026) is CHF 40. For a quick approximation, that CHF 40 is roughly equal to €44, £38.50, or $45.
Just keep in mind that this is the Swiss Franc base price. If you buy it online or in another country, the final cost will likely be slightly higher due to the exchange rate, plus any service charges, shipping, or payment processing fees (like those from PayPal) added by the vendor.
You can conveniently purchase the yearly e-vignette for Switzerland here.