To estimate the budget, let's consider the cost of renting three grand pianos. The cost of renting a grand piano can range from $100 to $500 per day, depending on the type and quality of the piano. For a semi-concert grand piano, a concert grand piano, and a studio upright piano, the daily rental cost could be around $200, $300, and $150 respectively. Assuming a rental period of one month (30 days), the total rental cost would be: $200/day * 30 days = $6,000 for the semi-concert grand piano, $300/day * 30 days = $9,000 for the concert grand piano, and $150/day * 30 days = $4,500 for the studio upright piano. The total estimated budget for the rental of the three pianos for one month would be $6,000 + $9,000 + $4,500 = $19,500. However, since the rental duration is not specified in the document, the actual budget could be higher or lower, depending on the rental period. Considering the uncertainty, a reasonable estimate for the budget could be between $10,000 and $50,000.