Hello,
I've jumped on the cheap tickets to Japan bandwagon and was also looking around for the cheapest method of getting Universal Studios Osaka tickets. It seems that you can only buy their tickets via their authorized resellers.
I've used the discount code KLKVISA17 to save $5.30 AUD off 2x adult tickets (2-3%?) with universal studios and I would imagine it would be something similar to Disneyland. There's other codes out there, just use your elite google skills. But from when using the Klook Checkout, it doesn't seem that the codes stack.
A minuscule saving but better then nothing I guess. Hope it helps someone.
On a separate note, Sanrio Puroland is 23 bucks on Klook which is cheaper then the 3300 JPY gate price as it stands. Indoor fun for the kids or the Hello Kitty inclined.
Klook also has a pretty good referral program, i have asked before to get it on Ozbargain, but had no luck. Give $US3 to every friend who joins klook and you get $US3 when your friend completes the experience.