You should know that the most important aspect of optimizing websites for search engines is to get links, but how do you get those links? It is important that you have great content so you can recieve natural links, but that is often not enough.
If you want to rank for competitive keywords you need natrual and artificial links, that is links that you create. Without these links, it is impossible to rank high for competitive keywords, or even to get indexed in search engines.
Webmasters figure out early on that link building is a pain in the bum, and very time consuming. In fact, many webmasters build links in the wrong way which can potentially harm their rankings!
Paying for links seems like a great option. Getting quality links is often very cheap, and involves little work. However, this practice is not as good as it seems.
First off and most importantly, paying for links is illegal. When you purchase a link on a blogroll, the feds will not show up on your house with gas masks, but you do run the risk of getting penalized by Google. If you do get penalized, it is nearly impossible to reverse it. So for paying for links, you could get permanately banned forom Google.
Note that Google only penalizes you if you purchase Dofollow links, that is links that pass on link juice which help with search engine rankings. If you purchase links with the Nofollow attribute, this is completely legal, but will not help your search engine rankings at all.
Also note that Google states that it only bans the websites that sell the links, not the websites that are linked to. However, I have heard of many people who have gotten penalized for purchasing links or building links to quickly. To be on the safe side, I recommend avoiding both practices. After all, you definitely don't want to get banned from Google!
Building links consistantly is the way to go. Not only will you avoid the worst case scenorio of getting banned from search engines, you will also save a lot of money. There are a huge amount of ways to build links yourself, so there is really no reason to pay for links unless you need the time.
If you can's spare the time, go out and hire a SEO expert who will build links legally for you. This may be less expensive then paying for links, but the results are much better, and you don't run the risk of getting banned.
The answer I and most other webmasters agree on is to stay clear of buying links, and to build your own. If you don't have the time, hire a professional to build links legally. This is the process that will get you the search engine rankings you desire.