Don't make capital investments until you are sure about market demand. The adage, "If I build it, they will come," is false when it comes to adding product lines that are not market tested. Although $5K isn't that much, it does represent a commitment in terms of time, space, ink, maintenance, marketing, overhead, stocking media, etc. I wouldn't make a purchase based on one customer commenting about buying something currently beyond my capability to produce. If ten customers inquired about that over a couple months, then I'd feel confident about proceeding with a capital investment such as buying a bigger printer and making a commitment marketing a new capability.