What type of online advertising should I as a retail packaging distributor?

[Jake]

You would need better targeted BtoB advertising to make it profitable, Facebook is better for casual sales to the general public, you have good personal demographic targeting but no real business targeting, other than identifying employees of some companies. Google Adwords is just too expensive for all but those with high converting sales pages create to Google specs in order to get high quality scores, it's a fast way to lose money if done casually. You can find first time user vouchers, I believe now you can pay in $25 and get $100 matching money from Google, so it might be worth experimenting, selecting the right 'buyer' keywords is essential. You probably want to stick to Adwords search advertising, though you can place ads on selected sites on their ad network.

You might be able to direct buy ad space on some industry related site through a broker like buysellads.com, buyads.com

The ideal thing would be to create a quality business web site with lots of original informative articles touching on packaging that would earn search engine ranking, so you end up getting the same keyword search based traffic as Adwords, but for free, some use outsourced writers to create content that the search engines value, starting at $3-$5 per article, up to $25 an article for an expert author.