Need a blockbuster on the cheap? Time to call in Robert Rodriguez

How much should a summer action movie cost? Lately, with the advent of 3D, and the ongoing love affair between studio execs and special effects, the figure has crept upwards. About $120m is the going rate. Sometimes two or three times that. Director Sam Raimi recently quit Spider-Man 4 after Sony cut his budget from $300m (£197m) to a mere $230m.

For studios, such profligacy can equal financial disaster. When marketing and distribution is factored-in, a $120m film generally needs to make $150m at the US box office to break even. And that's quite difficult. Tom Cruise's $117m Knight & Day was well reviewed, but has so far garnered just $49m. Many of 2010's other "tent-poles" also under-whelmed. The $110m A-Team made $70m. Disney's $200m Prince of Persia made $88m.

Into this troubled landscape strides the director/producer Robert Rodriguez. He was hired by Fox to make Predators, which hits cinemas this weekend. It cost just $43m. Rodriguez turns out to have a precious skill: churning out cheap movies that look expensive. He made his name with Mariachi, a 1992 action film shot for $7,000. None of his 25-odd subsequent projects have cost more than $50m. Sin City, his classy 2005 mega-hit, which grossed $150m worldwide, cost just $40m. How does he do it?

Commonsense. Rodriguez works in Texas, where film-makers get hefty tax rebates, and pays actors sensible salaries. He works to tight schedules (Predators wrapped in around 50 days) and uses limited CGI. He also employs a streamlined production team who do two or three different jobs each.

Most importantly, Rodriguez resists the temptation, endemic in major studio projects, to film multiple endings and extra scenes that would eventually end up on the cutting room floor. "A studio might take a week to shoot something knowing that they're only going to use a tiny bit. We do our editing first," he told me. "Fox actually asked me to keep this film completely away from them, because they'd spend too much."

The result isn't always note perfect. But it doesn't have to be. Every film in the Predator series has made at least $57m at the global box office. The 2004 schlock-fest Alien Vs Predator, which managed an approval rating of just 12 per cent on Rotten Tomatoes, made $172m. So regardless of whether this Predators is any good, it'll almost certainly end up in the black.