Pricing, pricing, pricing... One of those things most photographers have a love-hate relationship with. And one of those 'things' that is the corner stone of you being able to stay in business and be successful.
Here are links to two free resources on pricing portrait photography (& wedding photography) I've come across in the past. (Some of you might've come across them already, as well.)
The Sales and Pricing Remix - written by Philadelphia's children photographer Kristen Kalp - is a compilation of her favorite Brand Camp blog posts, about "establishing pricing, tweaking pricing, gaining confidence, and rocking sales". She is an excellent writer, knowledgeable and very witty. You will definitely enjoy her article collection and all her tips.
The Single Greatest Guide to Wedding Photography Pricing That Ever Was and Ever Will Be, as Stacy Reeves titled her free pdf guide, is originally catered towards wedding photographers; however she later on added a short chapter on how to adapt the advice in the guide to a portrait photography business.
Even though it is not a free resource, I have to mention Alicia Caine's 'Easy as Pie' pricing guide. One of the best resources you could invest in, as a photographer.