The best price I've seen in the last 6 mo on any brand of kid's multivitamins is around $0.08 each.  Even with a coupon, I haven't been able to beat Costco's price of $0.045 each.  Well, I just found a way to get them for just over $0.02 each!  WOW!

• Log-in or create an account with SHOPATHOME (if you are new to cash back shopping, you can learn more here)
• Search for "Puritains Pride"  
• It should be the first one to come up.  Click on the little picture of their website.
• Click on the green "SHOP NOW" button on the right
• Add one "buy 2, get 3 free" option of the 120 ct Children's chewable multivitamins to your cart: $25.98
• Add one "buy 1, get 1 free" option of the 100 ct Pre-vites to your cart for $7.29: $33.27
• Use code TE3QC2H during checkout to save $15 on any purchase over $30 and qualify for free shipping: $18.27
• Receive 7% cash back ($1.28) in your SHOPATHOME account within a few days: $16.99 for 800 vitamins or $0.021 each! 
• If this is your first purchase through SHOPATHOME, you will also earn a BONUS $5 cash back making your vitamins just $11.99 or $0.015 each!