There are actually two Adobe routes you can take. One of them is to subscribe to the creative cloud and pay a monthly fee of $9.99. For that fee you get the latest Photoshop and the latest Lightroom and all upgrades that come along. It's true that if you decide that you don't want to continue your subscription you will lose functionality in the programs. The other method is to purchase Lightroom directly from Adobe. It can be purchased from this website:
You can purchase Lightroom 5 right now and download it. If there are any more updates to Lightroom 5 you will get those updates free. You will be able to use Lightroom 5 "forever". You own the license to use Lightroom 5, and it will not expire. Just remember that when Lightroom 6 is released you will no longer have any support from Adobe, nor will there be any additional updates available to you. It is kind of like purchasing a used car. You can use it for as long as it works for you, but there is no support from the company.
The choice is yours, of course. Personally, I think the creative cloud subscription plan really works well. It's economical, and it ensures you that you will always have the latest versions of Photoshop and Lightroom. But if that plan doesn't appeal to you then you can purchase Lightroom 5 from the link I provided above. Lightroom 5 is an excellent program. But it's nearing the end of its lifecycle. You can purchase it now and install any updates that may come. And it's possible that there will be another update or two that might provide support for some new cameras. But when Lightroom 6 is released, if you want the new features and support for the newer cameras then you will have to purchase an upgrade version of Lightroom 6. Whichever one works best for you is something that only you can decide.
thanks so much for the feedback.