No 17% isn't much but you'd have to find/generate/create a customer base, pay for printing (small numbers cost more), pay for packaging materials - mine came in one of those cardboard tube thingies, and pay for postage.  Bearing in mind that people won't pay huge sums of money for a print/poster, you may well be worse off and could possibly make less than 17% of what you charge to your customer.

Not trying to put you off going for a local printer, just pointing out the possible expenses incurred :)

Gill