You can and should get reciprocal links free from other related sites. It is quite important to get good IBL (read more on the importance of InBound Links here
) which will boost your Google rankings, and result in more relevant traffic/buyers to your website.
All you need to do is find related sites to your own and request a link swap; they can only say no, or not reply! This is where paid for IBL can be of help, BUT ensure the sites are of good quality before paying or swapping links, read more on the above url.