"making a purchase" is correct and usable in written English.
You can use it whenever you need to refer to the act of buying something. Example: After making a purchase, I was eager to use my new phone.
Giving up, you leave the store without making a purchase.
Talk to your NEWA state coordinator before making a purchase.
94% of them conduct research online before making a purchase.
Of course, price is just one factor people consider before making a purchase.
Bill paying, phone help — even making a purchase can cost a dollar or two.
This allows companies to advertise to you if you leave their website without making a purchase.
"Free food samples are designed to guilt-trip people into making a purchase.
Unlike CherryCard, though, users of SocialVest must register before making a purchase.
Another surprise was how anxious customers are about getting their delivery after making a purchase.
He couldn't fathom making a purchase of Bear's size in just 12 hours.
Intrigued gamers should check the status of patch releases before making a purchase.
