This is just a quick overview of the various commission earning modules available on Squidoo and my experiences of them - bear in mind that people who focus on specific niches may find better success with certain modules than me.
Obviously! This is the 'old faithful' module - Amazon has almost everything you might need to offer, on every topic, and people generally trust the site. Due to both the wide range of offerings, and the reliablity and trust value, this is the steadiest, best earner for most people.
The various types of Amazon module allow you to show off your products in different ways, it automatically pulls the prices, and it looks nice on a lens. It's almost always best to select the products yourself, unless you're searching a very specific category that is highly unlikely to produce unpleasant surprises.
The maximum number of Amazon modules per lens is now twenty - You can of course mix it up by using your own affiliate account.
Not quite as big as Amazon (on Squidoo) due to the fact that it slows lenses down a lot more, and the listings can change, eBay is the next main earner for Squidoo lensmasters. How big depends on the topics people write about - eBay is good for crafts materials, rare items and collectibles, and second hand items. These may no longer be sold in stores (or on Amazon), or simply be a great bargain.
There's only one type of module, and it has to search for the latest listings everytime the lens is loaded, slowing it down significantly - this is probably the main reason that the limit is now five modules per lens.
eBay commissions are not as straightforward\. Each click from Squidoo is awarded a certain value by eBay and the total amount paid two months later. Squidoo divides up the payments among lensmasters who make sales - the amount is based on the listing fees, rather than the sale price. Because the click is attributed to the site it comes from, you can't use your own affiliate links.
Once the major print on demand site of the internet, Cafepress has successfully angered and driven away the majority of its affiliates. The module itself can be buggy and only offers one style.
Cafepress is good for the odd products, and the arty ones, designed by 'real people' - however, many are also offered through Amazon now. While Cafepress has a higher commission, it rarely seems to sell anything these days. Reporting is hard to track, as Cafepress only shows up as 'misc pending earnings' on the dashboard.
Zazzle is the new favourite POD site of the net, and it's my preferred spot to sell my own art. Unfortunately, while the Zazzle module is pretty, it doesn't give you a referral. Instead, all referrals go into the general ad pool.
If you want a referral from Zazzle (and they offer a nice 15%!), then you need to build your own links. This lens about using Zazzle lists all the helpful Squidoo lenses available on that topic.
iTunes and Amazon Mp3
Music sales tend to be rare, and the commission is tiny - but some people may be focussing on this niche more than me. I've never, to my knowledge, had an iTunes sale, but the reporting doesn't yet say 'itunes' that I know of. Each module may offer songs the other doesn't, and both look slightly different, so may suit different layouts.
There is currently a bug with the iTunes module (in Chrome, usually) in which the first track of each module on the lens autoplays. This is very bad!
No other module earns a commission on Squidoo.
Lenses that explain the various modules in more (or different) detail: