Groupon clone, claims to be open source but blatantly is not, pro version starts at $145, premium is "contact us" pricing.
Seemingly simple Groupon clone script for $69 USD, paid in Brazilian Real's. :-)
Good loooking Groupon clone with a seemingly low $200 price tag but a huge list of extra paid-upgrade modules.
One of the many sites that appear to offer identical groupon clone scripts for $400.
Nice(ish) looking groupon clone, $350. Appears to be built on PHP / MySQL. Looks like a unique product, unlike many of the others that appear to be clones of each other.
A groupon clone site from Agriya, an Indian software company. No pricing information readily available online. Featured in the New York Times apparently, hap tip Glyn. Built on CakePHP.