Next cheapest is £4.99 at DVDSource / Zavvi.
You're invited... A number of fighters are invited to DOA an invitational martial arts contest where combatants are then pooled against one another in a knock-out style tournament: the conquered is sent home while the conqueror progresses to the subsequent round. Four scantily-clad female fighters begin as rivals but consequently find themselves teaming up against an altogether mightier force..... Check your brains at the door and engage your sense of shameless high-kicking fun.
Don't forget Quidco at 4%.
I love this film, shameless glossy fun!