After I got my A&P I spent a year doing general maintenance and didn't like getting me or my tools dirty everyday. Yeah I know I can already hear the ridicule but this is a cool career field.
I didn't want to do general maintenance and tossed up between turbine engine specialist and avionics specialist. When opportunity came I chose Avionics and it was the best decision I ever made.
When you want to be good at something you have to give it your all. There is no half-ass way to do that, it's either all or nothing. I'll be the first to tell you I don't know it all but I sure am willing to learn.
As for the question about my A&P/IA, every certification you can get and all the experience you can gather is worth $$. People will pay when your reputation is good and the quality of the work you do is as well.
Bill