Try to read online articles and SEO forums like DP sitepoint, webmastertolk it will be giving you better result
read online there are so many articles regarding seo, so start collecting knowledge from those articles.
Yes you will find very Unique articles from ezinearticles.com, Digg, sphinn.com, seomoz.com/blog , etc. just use your research skill, there is no need to pay and you can also read seobook.com. Thanks Eric
That is a good opinion if you don't want to spend 100 dollars per month. I think there is tons of info on SEO for free. You only need to find and read it. Search on google for 10 best seo sites or 10 best seo forums. Read them regularly and you will get a good knowledge.
There are number of other sites where u can get free info.Couple of them are searchengineland.com and seorefugee.com. Also, u can get quality info from blogs and forums.There are number of groups online.Check out for them.
Get on SEO forums, watch blogs and check out articles. I guess the $100 would be worth it if it has all the best info is in the one spot and you do not need to go looking for it and it saves you time.