In around 10000 to 12000 rupees you can cover both places... fooding & lodging in kedaranath is not expensive & tungnath temple also close to kedaranath .. if you are budget travelers then you can cover these two places that much money.
I assume, youe start point as Delhi. Over Night Bus
Delhi-Rishikesh = 600-1000 Day Time
Rishikesh to Chopta = 600 Stay at Chopta = 500-1000 Chopta to Tungnath = Free
Trail is well defined. You won't need any guidance. Best Time: April-Oct
I visited both the places in the month of October, 2021. Although accommodation in Gauri Kund and Kedarnath was quite reasonable(GMVN guesthouses) but Chopta was disappointing in terms of quality and price. I would suggest if you wish to keep the budget to minimum possible, travel in groups of atleast 4. For a single person a comfortable budget is around 12K to 15k.