0th level spells are considered level 0.5 for the purposes of item creation.
So, spell level x caster level x 25 gp = 0.5 x 1 x 25gp = 12.5gp market value. But, it costs half of that to create the item. So, 6.25gp + 1xp to create a 0th level scroll with a caster level of 1.