Here are some basic considerations for a 'sale of goods' agreement:
Specify payment and delivery items: delivery date, location, method.
Specify approved payment methods: cash, credit, check, money order, Paypal.
Specify payment due date, or set forth a payment schedule in table format. Highlight any inspection requirements prior to sale.
Consider how to allocate risk in the event of a casualty/problem.
Do any warranties apply?
Consider specifying the consequences of each party’s nonperformance. Include a procedure for resolution of disputes (i.e., arbitration).
Note whether there are any attachments to the agreement (i.e., specification sheets)