Sunland State sells electronic products. The controller is responsible for preparing the master budget and has accumulated the information below for the months of January, February, and March.

Balances at January $1$ are expected to be as follows:

The budget is to be based on the following assumptions:

Each month's sales are billed on the last day of the month.

Customers are allowed a $3\%$ discount if their payment is made within $10$ days after the billing date. Receivables are booked at gross.

The company collects $60\%$ of the billings within the discount period, $25\%$ by the end of the month after the date of sale, and $9\%$ by the end of the second month after the date of sale; $6\%$ prove uncollectible.

The cost of each unit of inventory is $$20.$

Selling, general, and administrative expenses, of which $$2,100$ is for depreciation, are equal to $15\%$ of the current month's sales.

Actual and projected sales are as follows:

Calculated budgeted number of units of inventory to be purchased during the month of March