I have completed my 2 years of full time Post Baccalaureate Diploma in BC, Canada in May 2015, so when should I apply for Permanent Residency? And which is the best Province to apply where the PR rules are relaxed?
Maybe start here and see even if you are eligible http://www.cic.gc.ca/english/immigrate/eligibility.asp as there is no real timeframe to apply or not.
A bit of a challenge for anyone here to comment given little information you have provided such as language proficiency whether you have done IELTS, work experience foreign and Canadian, qualifications apart from mentioned diploma and are you inland or outland applicant. There are not really any provinces where PR rules are relaxed most have much the same requirements to obtain PR else everyone would be heading for the same province so the process is not supposed to be easy.