You always want what you can’t have — especially when it comes to beauty products. That’s why we’re getting the inside scoop from your favorite retailers on what’s selling out right now, how to sign up for waitlists, and where to go to find the next best thing. Because if everyone’s buying it, you know it’s got to be good.If we're going to bother with blowdrying and styling our hair, we want it to last. That's why we take the extra step to prep our damp strands with a heat protectant that's going to tame frizz, boost shine, extend the life of our style, and, of course, reduce damage from the dryer.Clearly, the rest of the world feels the same way, because just about every hair-care brand has a style-perfecting blowout spray in its product range. However, as you know, not all versions are created equal. So, when the folks at Birchbox told us its stock of Parlor by Jeff Chastain Smoothing Blowout Spray was completely sold out, we weren't surprised — we were intrigued.The product has over 11,000 mostly glowing reviews on Birchbox's website that detail everything from the product's intoxicating smell to its smoothing abilities. Since speaking with Birchbox a few weeks ago, the retailer's stock of the spray has been replenished, but we're betting it won't last long. Our suggestion: Pick up a bottle while you can, but if you miss your chance to give it a whirl, we've listed a few other blowout-perfecting options that have our seal of approval in the following slides.