"Magkano" is the question "how much?" in English. Unlike its English equivalent though, it does not apply to non-countable things. It is only used to mean or to ask for the price of something. So, when the word is used alone, it would be clearly understood that the price of something is being asked.
When asking for the price of a number of things or a single piece out of a group of items, we sometimes use "magkakano" instead of just "magkano".
"Magkakáno/Magkano ang kape sa Starbucks?" = What are the prices/What is the price of coffee at Starbucks? - You may use either one of the question words, but "magkano" is like asking for the average price, while "magkakano" would suggest your interest in knowing about the range of prices
"Magkakáno/Magkano iyan/'yan?" = How much is that? - For example, if you are in a wet market and you see a vendor selling fish on a tray, if you'd use "magkakano", it will be understood that you're asking about the price of just one fish. If you are to use just "magkano", it might be understood that you're asking for the total price of the fishes in the tray.
You might hear "mágka-ano" and it might sound very similar to "magkano" except that the stress is on the first syllable. "Mágka-ano" is a word that indicates a relationship between 2 persons or things, but the nature of the relationship is unspecified ("ano" = what). It has nothing to do with price unless "ano" is specified as "presyo" (price), i.e., "magkapresyo" = of the same price (also, to be assigned a price).
Magkano Example Sentences in Tagalog: (28)
How much is this?
How much is the soap?
How much is that?
How much is the rent?
How much money is still left in your wallet?
How much did you earn last month?
How much is the vinegar?
How much did you buy your shoes for?
Magkanomoibinebentaang cellphone mo?
How much are you selling your cellphone for?
How much (money) did you pay Anna?
How much (money) did you give Jack?
I don't know how much money I still have in my wallet.