yeah, definitely do, most of the sites selling ebooks just require a pdf upload (obviously the more industry standard you lay it out the better success you'll have) and amazon only require you to upload as html which automatically converts to the kindle file. I've not tried it yet, so am unsure as to how easy it is or if there are any costs involved but according to my online research it appears that there is no cost to upload to the sellers databases and you take home from 60% profit of sales upwards. Some sites require you to upload via publishers sites though.
And, again obviously, the more publicity you do for the item, the more you will sell. So, from my understanding, the main cost for doing this will be publicity.