Any advice on dealing with mass merchandisers?

Answer: : The best advice is to read the contact they will send you with a fine-toothed comb. Make sure you understand all of the terms and conditions, and ask for clarification if you do not. Summarize your concerns in a memo to management, referencing the specific clauses by page number and reference number. Pay particular attention to clauses that can cost you money including clauses covering co-op advertising funds, volume rebates, product return privileges, price guarantees, and penalties for late shipment, shipping errors, billing errors, etc.