Evike, Airsoft Atlanta, Airsoft Extreme, Airsoft GI, Airsoft Station are the big US retailers. Some of them still have Memorial day 10-25% off coupons going.
I've been doing airsoft for cross training for awhile now. I didn't believe in it until I saw how far the guns had come in the last decade. They aren't just toys anymore. Let me know if you have any questions.