There's a new generation of vessels emerging which is exemplified by Grimaldi's PCTC Grande Shanghai, claimed to reduce fuel consumption by 50% compared to previous-generation car carriers, and the NCL Vestland, a container feeder vessel similarly claimed to reduce.
The minimum shipping cost to Serbia from the USA today is $89. The final delivery price depends on the size and weight of the package, choice of courier service, and other factors.
For these containerized systems, starting at roughly 100 kWh and extending into the multi-MWh range, fully installed costs often fall in the USD $180–$320 per kWh range.