Just noticed the 'Rambo 1 - 4 [Box Set'] (DVD) is selling for the insanely low price of £4.47 at Tesco Entertainment. That's approx £1.12 per film! A new record low price for this boxset perhaps?
Anyway, next best price ATM appears to be £8.85 at TheHut.
Rambo: First Blood 
It's easy to forget that this Spartan, violent film, which begat the Rambo series, was such a big hit in 1982 because it was a good movie. Green Beret vet John Rambo (Sylvester Stallone) wanders into the wrong small town to find a fellow 'Nam buddy and gets the living heck kicked out of him by the local law enforcement (led by Brian Dennehy). The vet strikes back the only way he knows how, leading to a visceral, if unrealistic, flight and fight through the local mountains. Based on the 1972 novel by David Morrell, this film saved Stallone's then-foundering career and the Rambo character became the inspiration for countless political cartoons. But this film is Deliverance without the moral ambiguity. --Keith Simanton
Rambo: First Blood Part II 
After Rocky and its sequels, Sylvester Stallone cast about for another character that would bring him the same kind of box-office hit--and found it in disillusioned Vietnam vet John Rambo in First Blood, a solid little action thriller. So when all else failed, Stallone went back to the same well in hopes of recapturing the same commercial success. Which this film did. But where First Blood was a no-nonsense thriller that pitted Stallone against a worthy (and not necessarily bad) Brian Dennehy, this one is a sadistic chest-thumper in which Rambo gets to go back to Vietnam: ostensibly, he is there to rescue missing POWs, but in fact the movie was a lame excuse for him to refight the Vietnam War--and win. Audiences ate up the cruel Vietcong (and their Russian manipulators) and Stallone's bogus heroics, but it was strictly by-the-numbers action. --Marshall Fine
Rambo III 
And the hits just keep on coming. Sylvester Stallone, who can't seem to draw flies unless he's playing Rocky Balboa or John Rambo, went back to the Rambo well (or septic system, as it were) to show his well-known solidarity with the Afghan freedom fighters who battled the Soviet army in the 1980s. This time it's personal: his handler, Richard Crenna, is captured by the Evil Empire and so it is up to Rambo to leave his work in a monastery in Southeast Asia (no, seriously) in order to rescue him from the Ruskies. Ever wonder why the Russians had such a miserable time in Afghanistan? It was because Rambo took them on single-handed and sent them packing with hammer-and-sickle all the way back to Moscow. Cartoonish action, taken ever so seriously by Stallone, who was working desperately to scrape away the unsightly wax build up from his reputation. --Marshall Fine
Twenty years after the last film in the series, John Rambo (Sylvester Stallone) has retreated to northern Thailand, where he's running a longboat on the Salween River. On the nearby Thai-Burma (Myanmar) border, the world's longest-running civil war, the Burmese-Karen conflict, rages into its 60th year. But Rambo, who lives a solitary, simple life in the mountains and jungles fishing and catching poisonous snakes to sell, has long given up fighting, even as medics, mercenaries, rebels and peace workers pass by on their way to the war-torn region. That all changes when a group of human rights missionaries search out the "American river guide" John Rambo.
When Sarah (Julie Benz) and Michael Bennett (Paul Schulze) approach him, they explain that since last year's trek to the refugee camps, the Burmese military has laid landmines along the road, making it too dangerous for overland travel. They ask Rambo to guide them up the Salween and drop them off in order to deliver medical supplies and food to the Karen tribe. After refusing to cross into Burma, Rambo changes his mind and takes them, dropping them close to one of the Karen villages.
Less than two weeks later, he receives a visit from a pastor tellng him the aid workers did not return and the embassies have not helped locate them. The pastor has mortgaged his home and raised money from his congregation to hire mercenaries to free the missionaries, who are being held captive by the Burmese army. Although the United States military trained him to be a lethal super soldier in Vietnam, decades later Rambo's reluctance for violence and conflict are palpable. However, the lone warrior knows what he must do...