Often, as a general rule in Dickinson's poetry, the colour purple is used in two different contexts. Firstly, it is used to describe the beauty of nature and the way in which the sun rises or sets and creates a wonderful, indescribable havoc of colour on the sky and the land. Secondly, it is a colour that relates to the divine majesty of Christ and is often used to describe the colour of his robes, indicating his imperial nature.
In this poem, purple is actually used somewhat differently. The poem is a religious poem, as Dickinson thinks about what she could give to see the face of Jesus Christ. This makes her conjure up the best and most exotic goods that the world could offer, including the following:
Bags of Doubloons--adventurous Bees
Brought me--from firmamental seas--
And Purple--from Peru--
Purple therefore is used as part of a list of exotic goods from far off places, and is therfore used to symbolise wealth and exoticism, conjuring up images of priceless consumer items that emerge from lands of mysticism that were hardly known of. The point is, of course, that nothing would be too much in exchange to be able to look upon the face of Christ.