Correct

出售 vs 售 vs 卖

/ chūshòu vs shòu vs mài /
Strokes

Definition

出售, 售 and 卖 are all Verbs, which means “to sell”.

Example

卖 is the most colloquial, and the other two are more literary. Since 出售 is disyllabic, its syllabic collocation is different. In the following colloquial sentences, 卖 is used.
1
jiā
shāngdiàn
商店
mài
de
niánhuò
年货
yòu
biàn
便宜
yòu
hǎo
  

The special goods for the Spring Festival in that shop are cheap and fine.

2
Zhèzhǒng
这种
diàn
电器
xiànzài
现在
mài
shénme
什么
jiàqian
价钱
  
?

How much is this kind of electrical appliance?

卖 can be used in an abstract meaning.
3
shì
mài
苦力
de
  
,
píng
qi
力气
chīfàn
吃饭
  

I am a coolie, and I live by the sweat of my brow.

4
huì
不会
màiyǒu
卖友
qiúróng
求荣
de
  

He is the last person to betray his friends for personal gain.

售 is literary, and in example ⑤ it is better to use 售;卖 can also be used, but with a different style. In example ⑥ 售票处 is formal, so it is better to use 售.
5
Běn
diàn
cúnhuò
存货
duō
  
,
shòu
  
(
mài
  
)
wán
wéizhǐ
为止
  

The existing stock is not too much and will be sold out soon.

6
dào
shòupiàochù
售票处
mǎi
piào
  

Please go to the booking office and buy the ticket.

出售 is even more literary and mostly applied to big batches of merchandise. It is usually in collocation with disyllabic words.
In example ⑦ , it is better to use 出售.

In example ⑧, though 卖 can also be used instead, it has a different color.
7
Běn
diàn
shāngpǐn
商品
  
,
一律
jiàngjià
降价
chūshòu
出售
  

All the goods in the shop are on sale.

8
Zhège
这个
guójiā
国家
zài
guó
国际
shìchǎng
市场
shàng
chūshòu
出售
kuàngshí
矿石
ér
zhùmíng
著名
  

The country is famous for selling ores to the international market.

卖 can also mean" not to spare", 出售 and 售 have no such usage.
9
gànhuór  
干活儿
zhēn
mài
jìnr  
劲儿
  
!

He spares no efforts at his work. (not to spare)