Help needed in Canada!

I've been trying to grow my hair out for over 5 years and I never get past 1 or 2 inches past shoulder length before I get impulsive and schedule an appt. only to regret it later. If I had hair the lenght I really appreciate it (4 inches past shoulders) I wouldn't get tired of having them "in between"... you probably think that's ridiculous, but I used to have really long hair when I was a child and I miss that so much.

I'm in Ottawa, Canada, and I have no clue where to start. I want extensions to grow my hair out -- I have it at exact shoulder lenght right now and I hate it so much. My hair is really strong, thick, not oily, not dry, in between. Even if my hair was to thin out in the process I wouldn't mind at all! I'm just worried about losing lenght!

If I go around in the city to a few salons and compare prices could I get a good job or do you really need to have Insert Famous Hairstyler do it? I can't afford that. And what kind of method should I use with the kind of hair I have? Is 3 months the minimum or maximum extensions last?

Will my natural hair stay safe underneath? I want to grow it out -- I don't want to lose any lenght during the process of removing the extensions...

Thanks for any help.