The best answer is to register a domain name and forward it to the affiliate link - that way you can use any article directory.
Everyone is using articles so its lost its effectiveness - unless you are really good at keyword research and
SEO to make your articles rank well.
Articles for
SEO is more of a drip drip drip.. you need a LOT of them to make it work, but one good post on the front page of a well-ranked website is a LOT more effective.