Goggles

The goggles in the above shot seem nearly identical to ones I found at Coleman's Military Surplus for around $20.

In later episodes, O'Neill had more high-tech goggles, including some designed for Stargate by Wiley-X.

O'Neill's Goggles

In later seasons, O'Neill can be seen wearing these goggles. The used to be available at SeisSports.com, but all recent checks have shown them out of stock and I haven't found another supplier.

Again, for costuming, study the originals and then work to get as close as you can.

Also, be advised that these are not sufficient protective gear for Airsofting. Please only wear quality protective eye gear for shooting.