Here's a printable coupon for $2.00 off V8 V-Fusion Acai Mixed Berry. It costs $3.69 at Harris Teeter, so I'm guessing it will be around $3.00 at Wal-Mart, making it around $1.00 with the coupon. If you wait for it to go on sale somewhere you could probably get it for even less.
*Note: You will probably have to print this in Firefox. Those Smartsource coupons never seem to work in Internet Explorer!