- Existing customers' database. Do not hesitate to try to co-operate with existing websites, for example daily deals' providers, or providers of e-mail databases/direct mail service providers.
- Social media, but, unfortunately, Facebook doesn't accept penny auctions' ad.
- Banner advertising at popular portals, like, for example, online classifieds.
- PPC (Pay-Per-Click) advertising, like Google Adwords, however competition is pretty big
- Advertising at websites and forums, popular among penny auction lovers - www.pennyauctionwatch.com, www.pennyauctioncentral.com, etc.
- Offline ad - radio, TV, outdoor ad. As it is much more expensive than online ad, think about co-operation with your suppliers.