Correct

花 vs 用 vs 费

/ huā vs yòng vs fèi /
Strokes

Definition

花, 用 and 费 are all Verbs, which mean “to spend; to cost; to use".

Example

花, 用 and 费, all three words can take 时间 as their object.
用时间 is a general description of spending time;

花时间 indicates a special arrangement of time;

费时间 sometimes indicates an obligation to spend time on sth. or a waste of time.

In example ②, 费 cannot be used because it suggests a sense of passivity.
1
huā
  
(
yòng
  
)
  
(
fèi
  
)
le
shǎo
不少
shíjiān
时间
xué
学习
diànnǎo
电脑
  

He is willing to spent a lot of time studying computer.

2
Zài
xué
学习
diànnǎo
电脑
fāngmiàn
方面
  
,
zhēn
shěde
舍得
huā
  
(
yòng
  
)
shíjiān
时间
  

He is ready to spend time studying computers.

花, 用 and 费, all three words can have 钱 as their object.
In example ③ either 花 or 用 can be used, but in example ④ only 费 can be used, which indicates the sense of "being wasteful".
3
huā
  
(
yòng
  
)
le
300
300
yuán
mǎi
pǐn
礼品
  

She spent three hundred yuan on the gifts.

4
juéde
觉得
自己
zuò
fu
衣服
yòu
huā
shíjiān
时间
yòu
fèiqián
费钱
  
,
ér
què
wéirán
不以为然
  

I think it takes more time and money to make clothes by oneself, but she disaagrees.

花心思, 用心, and 费心, their object is similar, but the implication is different.
花心思 can either be commendatory or derogatory, while 用心 is generally commendatory.

费心 if applied to oneself, means "to consume one's energy"; if applied to other people, it is a polite formula for request.
5
Lǎobǎn
老板
xǐng
提醒
yào
huā
xīnsi
心思
zài
gōngzuò
工作
shàng
  
,
fǒu
否则
niánzhōng
年终
píng
评估
huì
shòu
yǐngxiǎng
影响
  

His boss reminds him to remain focused on work or risk a poor work appraisal.

6
lǎoshī
老师
zǒngshì
总是
仔细
yòngxīn
用心
zhǔnbèi
准备
shàng
上课
jiàn
课件
  

Teacher Li always prepares the courseware carefully and attentively.

7
Jīnnián
今年
de
shēng
生日
suàn
打算
guò
le
  
,
yòng
不用
fèixīn
费心
gěi
zhǔnbèi
准备
礼物
le
  

I don't plan to celebrate my birthday this year, so you don't have to bother preparing a gift for me.

费 implies "waste full, excessive consumption", neither 花 nor 用 has such a meaning.
8
Zhè
liàng
lǎo
chē
汽车
zàoyīn
噪音
  
hái
fèi
yóu
  

The old car was deafeningly noisy and guzzled fuel.

9
Zhěng
整理
zhèxiē
这些
wénjiàn
文件
shì
hěn
fèigōngfu
费工夫
de
shì
  

Sorting these papers out is going to be a long job.