Well, I think the easiest would be commenting in Do Follow sites. But yeah, good ones are hard to come by these days... Well if you must buy a do follow link, make sure the sites are related and it's not just from any site... It looks more natural for Google. Google actually has a way of detecting if the link is related to the site or not, just by looking at the words surrounding the link. If Google deems the link unworthy then they won't count it, then you just wasted your money.
Yes you can get do follow link you have do link building for your website please start with one way link building there are lot's of directories database website you can submit your website there. example are http://www.directoriesdatabase.com/
Most of the directory, social bookmarking etc links are nofollow links. you should do link exchange which are manual links and all are instant dofollow links. If you need service then you call me.
Hi, Add your site to social sites or social book marking sites and adding Article directory is good, but you can't get effective backlinks, best go for paid backlinks or do Link Exchange.
You can find at Subforum Buy-Sales-Trade on DP Forum here. There are many SEO agent selling their website backlink.
If you are interested in Fanpage Design with Do follow then www.mycitydial.com is good... I working on it
If your website/blog is in the fitness/fat loss niche, I can give you a dofollow link. PM me if interested. thanks
MyBlogGuest.com is a good source for high quality backlinks. However, you do need to writer good quality articles for the blogs you find from there. Also, look around on Fiverr. There are few good blogroll gigs and so on.