Tokyo to Osaka 13 days

Hi, I am on the 13 days budget trip to Japan but also would like to experience with bullet train to Osaka. Mainly, I just wanted to spend time in Tokyo and Osaka. I had booked hotel near Shinjuku station. I was thinking is there any chance someone can advice me with all the train passes in Osaka and Tokyo (as cheap as possible) I should buy when I land on the airport and also is that worth for me to buy JR pass if I’m only travel to Osaka. Please see below my itinerary. I’d be grateful if you can advice me. Thank you in advance.

Here is my itinerary:

22/ 03/201 Day 1: Narita airport to Tokyo
23/03/2018 Day 2: Tokyo
24/03/2018 Day 3: Tokyo
25/03/2018 Day 4: Tokyo
26/03/2018 Day 5: Tokyo
27/03/2018 Day 6: Osaka
28/03/2018 Day 7: Universal Studios
29/03/2018 Day 8: Osaka
30/03/2018 Day 9: Osaka
31/03/2018 Day 10: Tokyo
01/04/2018 Day 11: Tokyo
02/04/2018 Day 12: Tokyo
03/04/2018Day 13: Tokyo Haneda airport

Kind regards,
Poppy