How can I ... ?

Try posting ads on classifieds sites. You can also join those sites where they'll get people to view your site if you view theirs (startblaster.com is one).

First, Amazon pretty much has a monopoly on the market, so you'd have to make a huuuge investment to even be a noticable competitor, unless you market niche items.. sorry I can't go to your page, but be very certain that you have the necessary capital to even enter the market. Otherwise, a lot of emotional and financial losses could result. And most businesses, 9 out of 10, fail in the first few years, but kudos to you for trying.

In terms of the best advertisement type, know your audience and market to their needs. Once again, this is best if you have a niche. Especially online, in the relatively new field of e-commerce, reliability is very important. People want reassurance that you aren't going to rip them off. Become certified with Paypal, BBB and any other authorities to build a good reputation.

The best way, though, is through experience. There isn't a magic button, despite what some people try and tell you. See what works and what doesn't, track everything very closely, and you'll find out.

Best of luck to you.

what is your business. can you give more clue