In some places, lovers of Girl Scout cookies can now buy their Thin Mints and Samoas online -- with a few catches. Above, Girl Scouts sell cookies Feb. 8, 2013 in New York City. John Moore/Getty Images

Girl Scout cookies are back on sale, and for the second year in a row, lovers of Thin Mints, Samoas and other flavors, classic or new, don't have to wait for Brownies to come knocking on their door in order to place orders. Instead, customers can do it online or through phone or tablet apps. Here's how to get those cookies, available for a limited time only, online.

First, you can download a free app called Cookie Finder to smartphones and tablets, for both iOS and Android. The app helps you locate booths that will sell cookies once deliveries begin in late February. Customers also have the option of using the Digital Cookie platform to place orders and pay by credit card.

A few catches, however, make Digital Cookie less than perfect. First of all, not all councils and areas offer the platform. A list of local Girl Scout councils that do can be found here. Also, buying Girl Scout cookies online is not exactly like going to Amazon, choosing a box of Thin Mints and clicking on "Proceed to Checkout." Customers have to be invited to buy cookies by a Girl Scout herself. For those who don't actually know any Girl Scouts, it's back to the Cookie Finder app to find a booth.

But if your local council does use Digital Cookie and you do know someone who is a Girl Scout, she can initiate the sale or invite you to visit her cookie website. From there, people can place orders online, pay by credit card and have their boxes of cookies shipped to them.

This year's cookies include Thin Mints; Caramel deLites (aka Samoas), Peanut Butter Patties or Tagalongs; Shortbread, previously called Trefoils; Do-si-dos/Peanut Butter Sandwich; Cranberry Citrus Crisps; Lemonades; Savannah Smiles; and Thanks-A-Lot. The newest flavors, introduced in 2015, include the two gluten-free options Toffee-tastic ("buttery cookies with toffee bits") and Trios ("made with real peanut butter, chocolate chips, and whole grain oats") and an oatmeal raisin cookie dubbed Rah-Rah Raisin.

Girl Scouts sell roughly 200 million boxes of cookies annually, amounting to some $800 million in sales, the organization has estimated. According to Anna Maria Chavez, the CEO of Girl Scouts of the USA, profits go to "troop activities and projects that make their communities and our world a better place."