You won't be able to buy Simon's goggles anywhere. You'd have to make them by scratch. My suggestion is to make the goggles out of craft foam and clear yellow plastic sheets.
[~Future Cosplay Plans~]
Wirt (Over the Garden Wall) - 50%
Dipper Pines [Transcendence AU - "Alcor the Dreambender"] (Gravity Falls) - 50%
Stanford Pines (Gravity Falls) - 50%
Unbeatable Squirrel Girl (MARVEL) - 35%
Montreal Comic Con 2016 ll Otakuthon 2016