There are a few things you need to remember to have a wonderful time in Sagada.
1. There are some spots that in my opinion you really need a guide like Sumaguing Cave, Cave connection Lumiang-Sumaguing, Aguid Rice Terraces to Bomod-ok falls and Mt Ampacao Trek to Lake Danum. You can check out the Saggas (Sagada Genuine Guides Association). Other sites you may just ask any local to give you the direction like the Echo Valley, Pottery, Sagada Weaving.
2. Guide fees are set by the municipal council and are regulated. But you can always look for guides that offer whole tour packages or best to come in groups to cut down on costs