ProFlowers.com has 24 assorted roses /w free vase and a box of chocolates for $29.99 shipped.
Note : Cheapest would be to go to your nearby grocery store to pickup some flowers / chocolate, but if you have work/school, this is a slick way.
Update : Link is now fixed.
1. Click here to get $10 off
2. Click here to see the 24 assorted roses /w free vase + chocolate deal
Final Price : $19.99 + Ship($10)