What’s the ROI on spending more for a premium domain name?

Been in business 2 years on a domain that nobody can spell back to me over the phone. It’s on my packaging, my invoices, and my email signature, and I typically have to spell it out on every call. The one word version of my brand is taken and the guy holding it wants $4200. That’s roughly a quarter of what I have left for the year, and the same money could go to ads or rewriting my product pages. I don’t know what my options are outside of paying him. Has anyone here run the numbers on this? What happened after you bought the name you wanted?