Shopify's India price list for an online store. Basic is Rs 1,499 a month for a solo seller, with a 3-day free trial and then Rs 20 a month for the first 3 months, and a 2% fee when you use a third-party payment provider.
A product seller's guide to gross, operating and net profit margin with the formula for each and ways to raise them, linked to Shopify's free profit margin calculator.
A free calculator: enter your cost and either a price or a target margin and it returns the other, which is the fastest way to see the difference between markup and margin.