This is the link to US market with US$100 free credit with $30 top up http://searchmarketing.yahoo.com/arp/choose.php?o=US2258
Hi, if you ever used google adword then you can easily use yahoo search marketing.its really easy.but i think adword is the best.
Yup, you bid on keywords and when people search for these keywords, your ad shows up. If they click on it, you pay. If they don't, you get a free impression.