I would like to know what will be the cost for Episerver Certified Developer exam if I need to opt it remotely.
Have a look at this url: https://www.episerver.com/services/education/services-education-certification/remote-exams/ and check the schedule. There might be some schdule exams that you have in the pricelist, https://www.episerver.com/services/education/schedule-registration/#TargetAudience=Developers
This page lists all certification exams, locations & prices: https://www.episerver.com/services/education/schedule-registration/
This link works for me: https://inter.viewcentral.com/events/cust/catalog2.aspx?cid=episerver&pid=1&lid=10