I made an estimate of costs for running an ecommerce site below

Appreciate your comments
1) OpenCart
Cost of Software = 0
Cost of Extensions = USD 3k
Yearly Renewals for certain extensions = USD 200/year
Server Costs = USD 240/year or more, depending on traffic
Maintenance = Moderately Easy, 7/10
Cost for developed site = USD 3k to 10k
Rating of Costs = A
2) WooCommerce
Cost of Software = 0
Costs of Extensions = USD 4k
Yearly renewals of extensions = USD 2k/year
Server costs = USD 360/year or more
Maintenance = Easy, 8/10
Cost of developed site = USD 8k to 24k,
Rating of Costs = B+
3) OS Commerce
Cost of software = 0
Cost of extensions = 0
Yearly renewals of extensions = 0
Server Costs = USD 240/year or more
Maintenance = Moderately hard, 4/10
Cost of developed site = USD 3-5k
Rating of costs = A
4) Prestashop
Cost of Software = 0
Costs of Extensions = USD 6k
Yearly renewals of extensions = USD 4k/year
Server costs = USD 360/year or more
Maintenance = Moderate, 6/10
Cost of developed site = USD 10k-20k
Rating of costs = B-
5) Shopify
Cost of Software = USD 350/year or more
Cost of apps = USD 10.5k/year or more
Maintenance = Easy, 10/10
Cost of developed site = USD 10k - 70k
Rating of costs = C-
6) Magento Community
Cost of Software = 0
Cost of extensions = USD 7k
Yearly renewals of extensions = USD 5k/year or more
Server Costs = USD 960/year or more
Maintenance = Hard, 3/10
Cost of developed site = USD 25k - 100k
Rating of Costs = E