I have read very bad critiques on Search Ads. Also my experience is also not very good. Now I have them on one single journal and with only the keyword "leather journal". I don't want to spend too much.
To increase your sales you can add items, promote in tumblr, deviant, facebook, make a blog,... It's hard, and after a lot of work I am still not seeing good results, but I keep going on. Patience! :).