Check engine light finally...

I have owned this car for a month. Bought it with 135,000 miles on it. Finally Check Engine Light came on recently.
 
Symptoms I have had.
 
-. 3 days after I purchased it, it did not start one time, but it has been working fine except that.
-. When I came to a stop, it sputtered as if it was going to die.
 
The CEL came on 3-4 days ago, so I ran down to a local auto part shop. They scanned it and found two codes; 130 (evaporative issue) and 450 (O2 sensor). They also printed out what those codes mean. Then the CEL came off for a few days. It came back on yesterday and has been on so far.
I went to a garage that specialized in MECERDES ONLY. They said that evaporative issue was very tough to figure out and that the diagnostic itself would cost me 170 dollars. The rest of the repair? Only god knows. Could be 500? 1000? Who knows?
 
Now my question is... Is it worth to try DIY? The auto shop guy said, "Many people want to do DIY, but CEL is sometimes very complicated. Instead of paying $$$ for parts not related with your own problems ('cause normally they don't know what they are doing), have a mechanic look at it and fix it for you 'cause they normally know what to do."
 
I don't know it's worth try by myself or not. Any comments on this would be highly appreciated.

i say get a manual and see how hard it is if so pay someone u might make it worse and end up paying more in the long run.

Thanks for your reply. I have thought about it. I think it would be better to have someone look at it.
What I can handle on my own might be oil change, tune up, and things like that. Otherwise, I wouldn''t touch it.
Thanks again.