Most seo tools has a free version to test the software.You can download and try the following seo software for free.
1.Traffic Travis - Register and download the free version to check your website Google page rank Alexa traffic rank errors in web pages and sitemaps.Also monitor ranking of your website keywords in Google and Bing.Check how many pages indexed in search engines and total backlink count unique IP's unique domains and page authority of backlinks.Free version limits up to 5 projects 500 keywords to check rankings 50 top ranking sites to analyse and 200 keyword suggestions.
2.SEO Power Suite - This free seo software has 4 seo tools.Rank tracker to check keyword rankings in search engines Website Auditor to check website for errors Seo Spyglass to check and analyse backlinks and Link Assiatant to check backlinks and for link requests.Register to download the complete seo package.
3.Web CEO - Provides both online and desktop software.Online tools are Site Auditor to check website errors Keyword Tool to research keywords Backlink Checker to analyse backlinks and Rank Checker to check keywords rankings.The desktop software also have the same features.
4.IBusiness Promoter - IBP offers similar seo tools like the other three seo software.It gives step by step instruction to find the best keywords for your site optimize web pages and backlinks.Link management tool search engine submission tool keyword ranking checker and competitor analyse tool also available.