You'll tend to find that it's very difficult to gain traffic without gaining backlinks. They're basically the same thing and they should really be merged together. A link to your site which will gain good targeted traffic is probably a well-worthwhile and relevent backlink. Some are de-valued but they're far from useless. Submitting your website to good quality, relevent directories/categories can be a key part of a successful SEO campaign. Probably true. I know our analysis reports offer all the required information to completely optimise your website and backlinking campaign for SEO for that price, but that's another story. It may be possible to find other worthwhile services or help elsewhere for that price. Maybe even invest in a good SEO book or knowledge base to learn from.
Sponsor a few wordpress/phpld/website themes designed explicitly for mobile phones/technology - therefore you'll get lots of related backlinks to your site. You could also help the template creator in promoting it by simply posting on other template-related forums. Simple!