I used to love this show when it was on TV and still watch it now and again when I can. It's on UK TV Channel, Pick TV every morning at 10 at the moment. The figures are from Ground Zero Games who make their own 15mm versions of the Stargate characters Sam Carter, Jack O'Neill, Teal'c and Daniel Jackson as well as all the other poor saps who follow them on their journeys to other worlds and never return.
The are 4 character figures plus the 20 USAF Troops are up for sale on Ebay for £21.99
Here's the link for them, SG1 Ebay Link