The most common and most likely answer to this crossword clue is the 4 plus 5 letter word MAIL ORDER
I've seen this crossword clue in The Daily Telegraph
M
A
I
L
O
R
D
E
R
More clues leading to the result MAIL ORDER
- How to sell admirer snaps — look inside
- The ‘brotherhood’ broadcast Amazon’s business
- Daily sequence used for buying from a catalogue?
- According to hearsay, chap’s degree obtained by post
- A way to purchase flexible armour by post?
- Chap reportedly given degree by post
- How crusaders acquired their protection?
- Irishman returned book purchased by post
- Type of purchase made by man reportedly having class
- Millions suffer with religious community making such a purchase
Buddy explains!

The straight part
We know that "Type of purchase" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case type of purchase = mail order.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.
What does MAIL ORDER mean?
MAIL ORDER verb- To buy or sell goods to be delivered by mail