What's the best domain strategy for international SEO?

Hi All,

A newby here needs help, please!

My store is under development with my primary market being UK with a dot COM domain. I want to have just one main domain.

I do not want separate country ccTLD due to cost and inconvenience. The choice appears to be subdomains or sub-folders. I hear sub-folders are best for SEO. Content will be identical for each market. Prices will be at different levels, but in local currency. Prices will be all-inclusive, i.e. including shipping and duty/tax. What is the best domain strategy to help International SEO? Thanking you in anticipation.