Coupons.com has a great new $2 off Visine coupon available. Just head over and click on the "Health Care" section and for me it was on the second page. You'll be able to print two of these.
There are no size restrictions, so you should be able to pick up the travel size Visine's that sell for about $2, absolutely free! This time of the year, I always carry Visine around in my purse (I suffer from the world's worst allergies) so I always have travel sizes of it.