Most lumber yards will dress lumber (plane and joint) at $50-$60/hr, with mininum charge in place. Price can be higher if you didn't buy the wood from them. There may be a surcharge for your purpleheart if they consider it an "abrasive" material. Purpleheart is great at dulling blades. Should take less than 1/2 hour to dress your two planks, but consider the up-charges.If you have the muscle, you can dress the planks by hand with a scrub plane, #4 smoothing plane, and #6 or 7 jointer plane.
Do some research before deciding on a finish. Purpleheart can take a colour from magenta-red to purple to greyish brown, depending on finish and exposure to light/air. Start with the link below.
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