find out what KW competitors were been ranking for (bulk)

due to not much explosion of the internet in my rural country, some site with good seo, spam with garbage content, stole the local trafficssss away successfully (5-10k uv a day WTF)..

How can I detect which keywords were giving them traffic? seomoz can do that? If so any alternative? that one is expensive..

semrush

for just a few suggestions you can try ahrefs.com for free.