It all depends on what your current chem values are - could you please post the

FC
CC or TC
ALK
CALCIUM HARDNESS
CYA

You'll want to shock the pool (how much bleach you need depends on the CYA and % of the bleach) A lot of people add polyquat 60% for the winter - the bleach and the poly wipe each other out so shock first and hold it for a day or 2 then add the poly. (polyquat isn't required, but is a nice insurance policy against algae over the winter)

What kind of cover do you use?

$200 for opening chems is outrageous!! Unless your numbers are way out of whack and you're fighting algae ~$30 should do it

Please let us know your numbers and we'll be able to tell you what and how much of each to add.