Is it standard to tip in Peru?
Local guides do expect a tip though it's not obligatory and should only be given for a job well done. The standard amount is 20 soles per person for a full day tour and 10 soles for a half day tour. For drivers a tip of 5-10 soles is reasonable.
Tips for the guide, porters and cook on the Inca Trail and Lares Trek are not included in the tour price and you should budget for at least 100 soles per person to be divided between the team with usually 50% of that amount given to the guide and the other 50% shared between the cook and porters as you deem fit.