I just purchased a new home in San Diego CA. A few days after closing, i was casually looking through some of the popular sites (sdlookup.com, redfin etc) and noticed that all the sites had the sale price listed 5K ABOVE what it actually was. On enquiring with the sites, I was told that the value they reported is what they received from SANDICOR (San Diego County MLS) and/or MLS. This led me to understand that, intentionally or unintentionally, the listing agent reported a higher price.

I have written to MLS and also asked the listing agent to correct this..but nothing has been done so far. I wanted some opinions on whether an error like this is acceptable. I feel its wrong for incorrect sale price information to be out there since the information might be used for comps...however there is only so much I can do to get it corrected.

There is no justification, whatsoever to show a wrong price.  The listing agent has the duty to correct the values.  I am assuming it is a pure typo error.

Maybe you paid $5k more than you thought? County Recorder's office will show purchase price. If bugs you much---give that info. to MLS.