Spending a day at a salon is a tranquil experience surpassed only by swimming in a pool filled with mashed potatoes or having a hand model slap you to sleep. Feel the softer side with this Groupon. Choose Between Two Options $49 for a shampoo, haircut, blowout, and deep-conditioning treatment (a $135 value) $99 for a Brazilian keratin straightening treatment (a $300 value) Some hair-straightening products that claim to be formaldehyde-free include aldehyde compounds, which are similar to the carcinogen formaldehyde. Side effects may include nosebleeds, headaches, vomiting, and respiratory problems, among others. Learn more about the health risks here.