I charge £20 per half hour (£35 for one hour). For beginners, pre-grade students, I recommend a 30-minute piano lesson and for pupils preparing graded piano exams (Trinity College or ABRSM) and adults, 45 minutes to 1 hour depending on the grade and level.
For younger pupils, we do beat clapping, singing while introducing them to theory and to their first piano pieces through musical games.
I encourage daily and focused practice for each of my pupils as the most efficient way to progress and reach successful goals !