I don't think there are coupons currently available... The only offers I've seen are by scammers. Be careful.
Yeah, legit $150 off coupons expire in 2 days but I don't think there are any left. Beware of $100 off coupons, I don't know if Bitmain ever issued those. Always insist on using escrow and the scammers will go silent.
Escrow should be used always, and yes 100$ coupons are available. I was issued them.