Q: how long does the battery last on 2000 Honda Insight

Rookie cbe0621eac06868b3efe0d8d1d3611e23c60d3114864ea2ec19a68cfbd3eebab
and how much does it cost to replace the battery, is it easy to take it to a mechanic?
(1) Answer
I assume you mean the hybrid battery. I have seen many 2003-2004 Civic Hybrid batteries fail already, so a 2000 Insight is probably more likely than not to have a battery nearing the end of its useful life.

Try a local tech near you -- here's a list of possible folks to call:

They can point you in the right direction. The dealer, of course, is also able to help.