Magento Product Price History is an extension which maintains history of product price, every time when admin updates the price of product, price is also saving in price history table for maintaining log of product price.Quickly and easily see product price changes over time.
1 . Upload file manually – Extract it and then extract “Custom_Pricelog-2.0.0.tgz” and then copy all files app folder and then paste into your magento root directory, If you are using a different admin theme from default theme – be sure to copy app/design/adminhtml/default/default/layout/pricelog.xml to your theme layout folder app/design/adminhtml/yourpackage/yourtheme/layout/pricelog.xml.
2. Second way is from admin panel – Go to admin panel – System -> Configuration -> Magento Connect -> Magento Connect Manager and unchecked ” Put store on the maintenance mode while installing/upgrading/backup creation” option and browse file and upload it.
3. Clear Cache
4. Now follow provide documentation or goto admin panel menu, you will see “Catalog -> Product Price History” link.