"bulk buys" is correct and can be used in written English.
It is used to refer to buying large quantities of something. For example, "We got a great deal on bulk buys of printer paper."
But will these bulk buys offer the quality needed?
Conservative groups deny that they make bulk buys of ideologically appealing books.
For hardcore chocheads the Factory Zone offers bulk buys: for example, 8kg (yes, eight kilos) of Cadbury's Buttons for £39.99.
Unforgivable are the totes that come free with bulk buys at Superdrug, many of which are emblazoned with a perky, sick-making slogan (#lovinlife; #blessed; 100% gorgeous!).
But because the lists have safeguards supposedly to stop such activity, Forbes revealed that RSI breaks bulk buys up "into more organic-looking individual purchases" and offers on websites such as Groupon.
Bulk buys of rice, pasta, fruit juice (and meat, frozen vegetables and cheese if you have the fridge-freezer to store it) can knock your shopping bill down by half, but the downside is storage.
