44 Flattop is right. You're looking at the problem from the wrong end.
A normal 8 cubic foot household chest freezer costs about $400, and uses 1.5 kilowatt hours each day.
A chest freezer designed for off-grid costs ~1,200, but only uses 0.5 kilowatt hours each day.
It's not that much difference if you're on the grid, but a huge difference if you're using solar.
To provide 500 watt hours each day, assuming 5 hours of sun each day, requires 100 watts of solar panels. (rough estimate) To run through 5 cloudy days means you need a battery bank that can provide 2500 watt hours, or about 200 amp hours (rough estimate!)
So (roughly):
100 watts of solar panels - $400
charge controller - $200
batteries - $500
efficient freezer - $1,200
Total - $2,300
Compare this to using your existing freezer
400 watts of solar panels - $1,600 (inverter reduces efficiency)
charge controller - $200
inverter - $500
batteries - $2,000 (inverter reduces efficiency)
normal freezer - $400
Total - $4,600
This really is just a rough estimate, but I'd guess it's within 25%. ( adding 25% to the solar gives $2,875, subtracting 25% from the grid gives $3,450)
Do some searching online for numbers that fit your needs better. Some efficient freezers are made by Sundanzer, Sunlabob, and Sunfrost.
A good source of real world experience is Homepower.com.