'Love don't cost a thing' is a remake of 'Can't buy me love' (1987). Clearly, there are lots of similarities between the two and one might question the value of viewing the remake, having seen the original. However, there are two aspects of the remake that, in my opinion, are not as clearly emphasised in the original: father-son relationship and the importance of being open to unexpected, life-changing opportunities.
Alvin, the lead character, is a high-school student, exceptionally talented in mechanical engineering and extremely hard-working. The only thing that bothers him is that there is neither any partying nor dating in his life. His father acknowledges the issue and actively encourages Alvin to improve his work-life balance. Unfortunately, the dad's motives are not entirely based on what is good for his son. Rather, the father actually wants to become a more influential person in Alvin's life. In fact, the father goes so far that he even tries to distance Alvin from his "nerdy" friends, who might indeed be "nerdy", but are at least genuine friends. Eventually, the dad realises that he has been pushing Alvin along the road of self-destruction and rights his wrongs by providing the kind of help and support that Alvin really needs.
Paris is the lead female character, the most popular cheerleader, who used to date a guy who has become an NBA star. A life of luxury as a wife of a famous basketball player is what she thinks would be the best for her. It's not that Paris has no other interests, nor is that she is so hopelessly materialistic. Peer pressure and the acute lack of parental guidance and support have brought to where she is. However, the cracks are starting to open. First, Dru, the basketball start boyfriend, declares on TV that he is a "free agent" on the dating scene. Second, Paris gets the glimpse of how cruel her friends are when she witnesses how heartlessly they abuse the "nerds" who dare to walk or sit near them. Third, she damages her mother's SUV, driving it in direct contravention to her promise to stay clear of that car, as she is on her mother's car insurance.
Alvin sees that traffic accident as his opportunity to buy his way into the world of party-goers. He offers Paris to pay for the parts worth $1,500 and fix the car for free if she would pretend in public that they are dating. At first, she is outraged by the proposal, but due to the necessity to get the damage to the car fixed quickly, Alvin and Paris strike a deal that she would pretend to be his date for two weeks. During those two weeks, Paris introduces Alvin to her friends, helps him develop social skills and orchestrates his entire makeover. She also comes to realise that Alvin is the only person in her life who encourages her to pursue her real (music-related) interests, as opposed to settling for the status of the potential future wife of a cheating sports star. Moreover, Alvin impresses Paris with his exceptionally strong intellect, decency and sincerity. There is also that curious human tendency to get attached to the person whose life we are trying to change. Therefore, it is hardly surprising that Paris falls in love with Alvin by the end of the two-week arrangement.
As it is typical of romantic comedy plots, Alvin, otherwise being a very clever guy, fails to see this obvious development and also fails to grasp the real importance that Paris has in his life. He only values her contribution to his popularity. Therefore, he decides to cast her away at the end of the two-week contract. Furthermore, he rejects her when she tries to reconnect with him again. By doing so, Alvin not only alienates Paris, but he also puts his entire future in jeopardy. He is simply seduced by his ability to not only fit in but also to set the rules, evidenced by the crowd's adopting his ridiculous dancing style. Moreover, having abandoned Paris, Alvin develops a crass attitude, vulgar mannerism and egoism that far exceed anything displayed by the snobbish party-goers. He is now fully on the road to a complete self-destruction.
Fortunately for Alvin, Paris is the one who helps him return to the right track by publicly exposing their two-week deal and thereby ruining his ill-gotten popularity amongst the party-goers. That gives Alvin some space to reflect on how he has got his priorities completely wrong and through his subsequent actions and with a bit of encouragement and the necessary financial support provided by his father, everything falls in its place. Finally, with a bit of luck, he even gets an opportunity to impress Paris again, now with his bravery and selflessness, which prompts her to give him another chance. This time, he grabs the opportunity with both hands and there comes the happy ending.