At the moment, yes. However, I would use them with caution because your articles are not suppose to be for self promotion to send readers off to other sites. Hubpages, which is now under the Maven umbrella, doesn't benefit from sending people off their site. If you link to an Amazon product they do get a percentage of the profit.
If you use a hyperlink, it may be more acceptable to them.
However, I don't know if you are familiar with a site called Squidoo. It was similar to Hubpages and was bought by Hubpages some years ago. That site was full of people self promoting with very little substance to their articles. There were then people who would hype the views up in exchange for others viewing theirs. My point in telling you this is, we are not only writers and designers, we are users of the internet. You need to stop and ask yourself, if you as an internet user would want to see an article with a link to a Zazzle product. Is your article useful to the reader? Does it solve a problem? Does that link you want to put in aid the customer or is it just meant to fill your pockets?
Hubpages has done well to improve their site while many similar sites have fallen by the wayside. We as writers, I feel, have an obligation to raise the bar as well and not look for a fast buck.