Wide-format printers turn digital files into gallery-quality art. A solid machine should last five to seven years if you treat it well. Buying a high-end model now prevents the frustration of clogs and fading that come with cheap consumer gear.
Wait for the late summer sales. Retailers drop prices to clear space for the new school year. Last year's flagship model is often the better buy because the tech hasn't changed much but the price tag has.
This 18-month window is a strict deadline for your budget. If you still have a balance when the period ends, the standard interest rate will apply to the remaining amount, which makes your printer much more expensive.