<font face="Verdana, Arial, Helvetica, sans-serif" size="2">Originally posted by TimMeineke:
Since this math is all new to me, is buying the larger boxes with the 250 mile certs the most cost effective way to do this?</font>
At the present time, it looks like it is. Periodically, though, you can find the products with the 100 mile certificates on sale, and use coupons to knock the price down to $2/box or less.
At that price point, the 100 mile boxes are more cost effective.
Mike