Planning a 3-Month Trip to Japan: Is a $3,000 Budget Realistic for Two?

I'm new to traveling and recently spent 17 days in Saudi Arabia. Next, I'm planning a 3-month trip to Japan with my mom, primarily staying in the countryside. My budget, excluding airfare, is around $3,000 for both of us. Given that I'm still learning about travel, I'd like to know if this budget is realistic for Japan or if I should plan for more. Also, do I need to negotiate prices for everyday purchases in Japan like I did in Saudi Arabia, as I'm not very comfortable with haggling yet?

Let me know if the budget seems sufficient or if I should aim higher.