Deep Down is a free to play downloadable game. Its business model involves players downloading the game for free and then providing revenue to Capcom via microtransactions, possibly bound to the game's player housing and more. Yet listings for the game have popped up on multiple amazon stores, and some actually have a pricetag attached.

While on Amazon US lists the game without a price as "currently unavailable," Amazon UK, Amazon France, and Amazon Spain list the game with a £49.99 or € 69,99 pricetag. The most interesting element is that you can actually pre-order the game, and according to the retailer's sales rankings customers are actually already doing so.

While there are other possibilities, this could be a hint to plans to release a packaged version of Deep Down, or a premium PSN option (since now Amazon sells PSN games as well), that could include some or all of the initial benefits usually offered with microtransactions and possibly a certain amount of in-game currency in a single promotional deal with the game.

This kind of release definitely isn't new for free to play games, so it's most certainly not unlikely.  Capcom would get a degree of initial revenue and players would be able to play at least for a while without worrying about microtransactions.

Of course there hasn't been any official announcement about it yet, so we have to take the listings with a proverbial grain of salt, but it wouldn't be the first time that Amazon listings give a hint on what's to come.