2001 Echo Shocks/Struts

[runnerxc]

Hi all, first time post.
Found this forum and thought this would be a good place for some help. i have a 2001 Echo and need to replace both front and rear shocks/struts. I know virtually nothing about car repairs so wanted to know if someone here knew how much this should cost. I'm just trying to get an idea before I take it in so I know a ballpark figure.
Also, is it better to buy parts online yourself and have them installed? I generally feel like a mechanic is always taking me to the cleaners with how much stuff costs sometimes.
Any help is appreciated.
Thanks all.