What is the best link to buy for Rental Classifieds site?

[openfire]

I have a brand new Rental Classified site that is free to post rental ads on, and I am looking to buy one or two premium links to help drive some traffic to the site.

I'm wondering what link/s I should buy?

I want the best bang for my buck and I am willing to spend maybe $50.

Should I spend the whole $50 on one good link, or divide the money up and buy several cheaper links?

If one just one link, what link?

Thanks