"How much is it?"
The これ、それ、あれ、distinctions here are subtle so can see why it's confusing some. The question is "How much is 'IT'?," basically implying you are pointing or looking at something close to the person you are asking, which is what それ is for. Think something behind a glass counter at a bakery or when at a ticket booth, それ doesn't mean the word "IT" translated but the use here is closest to the use in English in these kind of circumstances.
これ would be "How much is 'THIS'?" as directed something close to you instead. And あれ would be something further away from both of you so more like "How much is 'THAT'?," which is another question also asked in this same section.
More precisely, いくつ is asking for a number. As in, "how many?" You only use it for countable items. So you couldn't use it to ask about a quantity of water, or a quantity of rice. Unless you genuinely wanted to ask someone how many grains of rice there were in a bowl. But you might not get a helpful answer to that.
I'm noticing a trend and I'm wondering if it's right. いくつ has been used for "how many things?" and いくら has been for "how much money?" Now i learned that つ is used as a counter for things, so does that mean that ら is a counter for money? And does that mean that いく means "an unknown number"? Like you can put いく next to any counter and it will mean "how much/many of that thing"? I hope this makes sense.