Based on my experiences, following things may be helpful for you to start the car.
1) Buy one bottle of Battery Protection Liquid, $2.50-3.00 each. Spray on the bolt part of the battery routinely.
This is very useful for starting car in damp weather.
2) Buy one battery booster. 300A will cost 59
400A tyoe costs 79.99
This can also be used to backup battery.