I've got some great kits up for just $2.00 at DigiScrap Station - FRIDAY only so be sure to snag them fast! Follow the link and click on the FRIDAY EXPRESS tab on the left and you'll see all of the great $2-buck offerings!
I'd rather make my own Valentines for my kids' classrooms than buy them. This year, Jack wanted SPORTS and Luke wanted STAR WARS (no big surprise there!). So I made these 3x2" Valentines and printed them off on Avery's 5163/8163 Shipping Label Sheets (they print 10-to-a-sheet).
Then I bought these small 3.25"x2.25" paper baggies from JoAnn Fabrics and filled them with a few Hershey Kisses, folded over the top, and stapled it closed like this:
The labels are actually 4x2" long, but you need space for your kid to write who the Valentine is going to and sign his/her own name (hence why my images are 3x2").
If you think you can use either of them for your own personal use, download links are below. Obviously these are for your own PERSONAL, NON-COMMERCIAL use since I do not own the copyright to the images used.