Private person/firm

English as a Second Language English Vocabulary, Grammar and Idioms
1

Hello,

When you want to purchase something (for instance like a truck) you can either buy it as a private individual/person or on your firm/company.
How can I say that:
“We can buy the truck…”. I don’t know what preposition to use and whether the terms “private person” or “firm” are used correctly.
Thank you so much for your help.

2

We can buy the truck on our own behalf or on behalf of the firm/company.

3

We would like to buy the truck as a private sale.
We would like to buy the truck on behalf of a company.

This will be a prvate purchase.
This will be a business purchase on behalf of … firm/company.