Singaporean girl 1st time going to korea?

Hi all, I m planning to go to Korea for e 1st time to count down the New Year….

I would like to enquire on some questions:

1) which Singapore travel agency offers the best tour packages with cheapest costs?
2) Which flights offers the cheapest air fares? Departure from singapore
3) Does stopovers means that I am allowed to stay at the stopover country for a few days before proceeding to Korea?

Thanks.