The deal is expected to be completed early next year, with eBay buying all the company's shares. EBay will also buy equity in the UK's SecretSales.com and Japan's Brands4Friends.jp.
Based in Berlin, Brands4Friends is a shopping club with 3.5 million members that began trading in 2007. It offers club members daily discounts, usually on fashion goods from 600 fashion brands.
Doug McCallum, senior vice-president for eBay in Europe, said: "With the acquisition of Brands4Friends, we will enter the online shopping club market with an established and dynamic partner who has the expertise, relationships and passion to match our own ambition.
"We expect many eBay customers will enjoy great deals on international fashion brands by joining the Brands4Friends community."
EBay has highlighted shopping clubs as a significant growth area, with 20% of fashion sales made online across Europe. The company is currently benefiting from a boost provided by the freezing conditions in the UK.
BBH parted company with eBay earlier this month due to "marketing changes" within eBay, which has included marketing director Alex Marks leaving the company to set up his own consultancy, Fresh and Frank.
Earlier this year, eBay launched its own fashion website, accompanied by a high-profile marketing push.