DB's site usually gives a full fare and a standard rate exclusive of the date. I just did a check for Nov 20 leaving Amsterdam Central going to Berlin HBF and returning on Nov 21. It shows that the standard fare for two 1st class departing tix ranges from 138 euro to 404. The return trip is 276 euros. If you select 2nd class the departing trip from Amsterdam ranges from 74 to 218 euro and returning is 156 euro.