There is no difference. You get all the features in all plans.
FREE Updates, FREE Sync, FREE Online Support, FREE License Transfer is included in all plans. But yes, higher the plan, more the saving.
1 device 1 month plan: 500 INR
1 device 1 year plan: 500 x 12 = 6000 - 50% discount = 2950 rs
1 device lifetime plan: 2950 x 10 = 29500 - 68% discount = 9440 rs
Check out pricing: http://bookkeeperapp.net/subscription/
To purchase, just login on website: https://bookkeeperapp.net/log-me-in/
Choose your plan and make payment. That's it!
It will be activated instantly.