I used the remote pilot study guide from the FAA along with other documents on the site. Googled for info, watched some videos, and took some online sample tests. Downloaded Remote Pilot Prepware by ASA to my iphone/ipad. It has over 450 study questions in the same format as the exam and was only $4.99. Well worth the money.
Took the test 3 days ago and got a 92. If you can study about an hour or so a day for a month you can do it yourself using the many online resources. I started the study process 3 weeks before the exam date with no prior knowledge or experience in this area.
Search the online resources, spend some time reviewing them, and then assess if self study is good for you.
Good luck...