JR pass or single pass more worthwhile?

Is it more worthwhile to purchase JR pass compare to single pass if I travelling
1- from Narita airport to Kyoto
2-Kyoto to Osaka
3-Osaka back to Tokyo

If you do the round trip within seven days, a 7-day Japan Rail Pass will pay off. If you require more than seven days, regular tickets will be cheaper.

If you really want to save money, I recommend to take the night bus:
http://www.japan-guide.com/e/e2363.html

I only travel three times in a row meaning from Tokyo to Kyoto, Kyoto to Osaka and Osaka to Tokyo and the duration is less than 7 days, so is JR Rail pass more worhtwhile/ And roughly how much will it cost?

Single tickets from Tokyo-Kyoto, Kyoto-Osaka and Osaka-Tokyo may cost 490 yen less than the cost of a JR rail pass. But the pass is worth buying if you can include the rides to and from Narita within the 7 days.

You can do the price calcuation here:
http://www.hyperdia.com/cgi-english/hyperWeb.cgi

You can also use the pass to go around Osaka on the JR loop line. While in Kyoto you can also use the pass to go to Nara and/or the Fushimi Inari shrine (or to Arashiyama) for a 1 day trip.