Changing prices in bulk can be done through importing a CSV with two columns – headed by a ‘sku’ column and a ‘price’ column. See below sample csv
For each existing SKU, set the new price and save your CSV file.
Once completed, go to SYSTEM > IMPORT/EXPORT > FAST BULK PRODUCT IMPORT > DATAFLOW – PROFILES
Click on the ‘update product prices’ profile:
Now choose your CSV file and run the profile: