Many SEO companies offer paid search submission. But don’t get sucked in. It doesn’t cost a penny to get indexed by the major search engines (Google, Yahoo, MSN). Therefore, it shouldn’t cost you anything either. In fact, you don’t even need to submit your site to the search engines. Simply acquiring high-quality back-links will ensure that your site shows up on the search ranks.
In terms of SEM, PPC advertising is a paid form of search marketing. However, this is a completely different concept and has nothing to do with search engine submission. PPC is not included in the organic results and campaigns end when your budget runs out.
Some of the smaller search engines may charge a fee for inclusion, but ignore them. They compose such a small percentage of overall search traffic that inclusion is insignificant. Keep in mind that Google, Yahoo, and MSN comprise over 85% of all search traffic. For this reason, focus should be placed on these giants. Putting time and effort into the ‘rest’ is likely not a good use of resources, unless there is a vertical or niche search engine in need of particular attention. Thankfully, the smaller, lesser known engines tend to mimick the algorithms and principles implemented by the big guys, saving you time and hassle in the long run if you do plan on optimizing for all engines.