Read the product descriptions.
Also, if you select the Photography category in MAS, there's a section devoted to apps that work with Photos. However, I'm not sure that it's a comprehensive list.
I fail to understand this whole, "Higher price to cover Apple's commission" thing. Well, I understand it, I just disagree with the tactic. The tactic is saying, "We don't need a middleman." Or, in more extreme cases, "The middleman is a leach." Sorry, as someone who's been in businesses where we gave a 40-50% discount to retailers and over 50% to wholesalers, 30% sounds like a fair deal to me, easily accommodated by the price we'd set for our products. The retailers were able to sell far more of our goods than we could have ever sold ourselves, more than compensating for the lower amount we collected on per-unit sales.
So I think that whole "Higher price to cover Apple's commission" is a dumb tactic. A producer of goods who wants to sell only direct-to-the-public, or undermines the retailers who are also selling his products is being short-sighted, greedy, and ultimately, doomed to make less money. The point of using retailers, wholesalers, and other middlemen is that they expand your retail reach. It's generally better to have your goods in every suitable retailer than only in your own store (like Apple, which sells in its Apple Stores and at its web site, but has a far larger network of authorized retailers). No matter where the potential customer goes, he/she is exposed to the producer's product. Wherever the consumer prefers to shop, he/she will be able to buy that product. The retailer works to bring consumers into his/her stores, exposing more people to a product than a producer can reach alone. Widespread availability is also one of the ways a product gains credibility.
In most businesses, product producers set a suggested retail price that allows for discounts to retailers and wholesalers, commissions to sales agents, etc. When selling direct to the public, those product producers may offer discounts - generally, the discount is less than the discount they give to retailers - there's little point to running a retail store if you make no more retailing than you do selling wholesale.
In terms of consumer psychology, a discount at a "manufacturer's outlet" is better than regular price. The regular price sets the perceived value of the product, no matter where they buy it. The discount says, "We're making more than we do when selling through other retailers, so we can pass some of those savings on to you." It's better for the consumer to believe that the regular price is a fair value than to think that the price at retailers is too expensive, or artificially marked-up. If they believe the latter, retailers have a harder time making a sale, which reduces the efficacy of having retailers in the first place.
