A good illustration setup should last you four or five years without dragging down your brush strokes. Buying a premium screen and pencil upfront hurts, but cheaping out usually means replacing a sluggish screen in eighteen months. You want to buy once, not twice.
Timing matters here. Late summer brings back-to-school bundles, which is often when last year's model drops in price. If the screen refresh rate and stylus tech haven't changed in the new release, buying last year's stock gets you the exact same drawing experience for less.
Keep in mind that a 0% rate is a timeline, not free money. If you still have a balance when the 15 months end, regular interest kicks in on whatever is left, which makes that tablet a lot more expensive.