询问价格时大家可以说：
Whats the price of the+名词单数？
假如对复数价格提问，有 What are the prices of the shoes? 这种说法吗？还是说 Whats the price of the shoes?
假如询问苹果、桌子等其他可数名词价格时，用 What are the prices of the apples / desks? 行不可以的呢？还是干脆都用单数的呢？
price表示“价格”、“价钱”的意思时，是可数名词，复数形式是 prices，比如：
Prices are going up. 物价正上涨。（《薄冰英语惯使用方法词典》 price 词条）
询问价格时大家可以说：
Whats the price of the...？
What price is the...？
How much is the+ 单数名词 + ？
How much are the + 复数名词 + ？
比如：
Whats / What is the price of the car？
= What price is the car？
= How much is the car？
这辆汽车的价格是多少？
How much are the apples？这类苹果什么价格？
【注意】the price of the 后面可以接单数名词或者复数名词，比如：
The price of the vegetables is going up. 蔬菜涨价了。
The prices of the watches are very low at that store.
=Watches are very cheap at that store. 那家店的手表非常实惠。（《外研社英汉多功能词典》price词条）
所以，What are the prices of the shoes? / Whats the price of the shoes? / What are the prices of the apples / desks? 也是正确的。
但，不可以说：How much is the price of...?
