Can it be cheaper - to use just wooden pencil , but with electric pencil sharpener?
I found an article with comparison by price and reviews https://prizedreview...ncil-sharpener/
But is it reasonable? I don't know much about prices of art supplies and their caracteristics
It totally depends on the price of the sharpener since even a premium quality wooden pencil is typically less than $2.
Most folks I know who like wooden pencils seem to prefer mechanical hand crank sharpeners over electric sharpeners. I certainly do. I've got a $10 exacto mechanical sharpener which does a better job than the expensive Bostich electric sharpener I received as a gift some number of years ago.
If price is your primary concern, my recommendation is to get a $0.99 tap knife or $3 utility knife from the hardware store and learn to sharpen your pencil the old fashioned way. Even if price isn't a concern, sharpening a pencil with a knife can be a lot of fun since you can experiment with tip shapes. I happen to like sharpening my pencils to a wedge shape rather than a round point so that I have two sharp edges to write with and also have the option to get some line width variation like with a stub fountain pen.