Can you please share your tools which display different results?
The best way to get ranking position is to register at Google Webmaster account and verify your site. You will find out your website's rank position for Top Search Queries. here you can
visit Google Webmaster Tools.
Other free tools I may suggest are as follows:
1. CleverStats free search engine position software for webmasters to monitor your Google rankings.
Click here to visit.
2.
GoogleRankings.com - Check the ranking of a web page in Google. You will require Google's soap API. (I have not used this recently)
3. You can also check ranking using SEOMoz Tools, but they are paid one, about $80 a month cost.
Click here to visit
I hope these tools will help, still i will go with Google webmaster tools.