Best cheapest paid themes for elgg 1.8.1.6 ?

i am making a education site we will need a page for pdf's and videos for logged in users and thats about it! not a hard site, i could use a free theme but want to fully customize it like the colors of the site and need a menu for pdf's and videos i can do this my self though i need a paid theme for originality but not willing to pay more than 50 dollars!