Will my target audience realistically spend this amount for the product? Again, your reputation is on the line here. Is the product you are thinking of promoting priced reasonably for your audience? When I was writing my ebook, I was stuck on pricing. I asked around for opinions. A number of people suggested I price my ebook at $47! Their idea was to price according to value, not size. In my mind that was crazy. My network was composed of a lot of stay-at-home bloggers, and my collective audience was comprised mostly of people without a whole lot of disposable income. There was no way anyone was going to pay $47 for my 30-page ebook.
Always disclose your affiliate relationship. Most visitors will probably understand that graphic ads will lead to your getting paid, but if you write a review or use an in-text link as a recommendation, you want your readers to know that may lead to compensation as well. This ensures you retain transparency and trust with your readers, but also, it's required by the FTC's endorsement rules.