This is the 14934th most frequent Russian word.
подешевело
"Подешевело" means "became cheaper."
The word "подешевело" describes the reduction in cost of electricity.
С тех пор, как поставили солнечные панели, электричество в доме подешевело.
Since they installed solar panels, electricity in the house has become cheaper.
Here, "подешевело" emphasizes the change in price of the book during the sale.
На распродаже эта книга подешевела вдвое.
At the sale, this book became half-price cheaper.
In this sentence, "подешевел" refers to the lowering of transportation fare costs.