Where to buy affordable window guards in New York?

If you're purchasing a large quantity, consider visiting a local hardware store and negotiating a discounted price for a bulk order. Smaller stores in the outer boroughs often offer competitive pricing for customers who are willing to make a substantial purchase.

I assume you have standard two-panel windows with vertical frames? Do you need to fully open the window or would it be acceptable to limit the opening size to a certain measurement? What's the intended purpose - to prevent children from accessing the window or to keep cats from escaping? I may have an alternative solution, but I'd need more information. If you can place an order online, there are several websites that sell four-prong devices for around $25, plus shipping and tax.