Depends on what outlets you have around you. I don't know anyone who offers a significant break on a case (48 cans) or 'half' case as most are packed nowadays.
Back in the old days, the companies didn't offer significant discounts until 12 cases were purchased for one shipment. For an individual or small facility, that's just way too many at one time.
If you're buying retail, I used to buy a 'case' a week for round robins, using coupons at the local big box store(usually 20-25% off total purchase).
In the 40 years I've been around tennis, there has never been a reasonable sized 'bulk' purchase deal that meant much to the final consumer. For a pro running tournaments, free freight and 8% off wholesale is a big deal. For an individual, the numbers just don't mean a whole lot UNLESS you are paying say...over $3/can for Championship balls. THEN, you might be able to find some savings in a bulk purchase. If you're an individual paying $2.25 per can at retail, I don't think you'll find significant savings in a quantity that makes sense.
Heck, it's an election year here in the States...gonna be hard to get a straight answer to ANY question.