One of the things we constantly have to deal with in this industry is that popular items go out of print regularly. Manufacturers see more sales on new items than on backstock, so they put their cash into the current new release rather than doing a reprint of their core game. However, we can’t easily get a new customer interested in a product line if we don’t have the core game in stock.
Multiple Suppliers
Maintain accounts with multiple distributors. You need at least two, and having three or four is better. When one is out, check another. If you’re concerned about the stock levels of something, ask your sales rep how their supply is. If it’s running low, you might have to buy up a longer supply than you normally stock. See if the manufacturer has a supply on hand that it hasn't shipped to distribution yet. Buying direct might fix a supply problem.
Networks
Other stores might have extras in stock. What sells great at one store doesn’t sell well at every single store in the country. You might be able to trade your Cardfight Vanguard that’s not moving for the Heroclix that your local community wants. Check out online networks like the Delphi forums or game retailer groups on Facebook.
Give Feedback
Give manufacturers feedback through their Facebook page, e-mail, industry gatherings like the GAMA Trade Show and GenCon, and other opportunities. Let them know how their stockouts affect you. Point out the sales loss and ask when they expect to move more product into distribution.
Spend More
If you deal in second-hand games, you can increase your buy price for high-demand items. Instead of 25% store credit, offer 40%. As always, you might offer product instead of cash. For a product you normally pay $10 for, offer to trade it for a $15 product. Your cost is less than $8 cash instead of $10 cash, but the customer gets a better value. Accepting a lower profit margin isn’t ideal, but it’s better than losing customers due to stockouts.
Change Focus
If Vallejo can’t keep their American products in stock for long periods of time, consider carrying Privateer or Reaper paints. You shouldn't be dependent on any single product line for your sales. You should be prepared for a slowdown or sudden crash of any product line. If it's that hard to get, you're probably not seeing that much in sales from it anyway.