I'd like to know if a low price code reader is a good investment for doing some small diy diagnostic and repair. There's one I found interesting at 80$
thank you for answering!

 

any scanner is good to have, better ones will scann all types of codes while some only read engine troubles. But autozone/ or most auto chains will scan your codes for free. so its purely choice.

 

Can you link to a description of the product you are looking at purchasing?

With scan tools, it is nice to have them, but if all you are going to get is the basic one, your best bet would be to save your money and just go to your local Autozone or Advanced as roost suggested.