However, I do so with one reservation, buying music from Spotify - using its strange "download credit" system is generally very expensive - much more so than Amazon for example. So, while I whole heartedly recommend listening to tracks/albums on the service I cannot in all consciousness recommend you buy from them. Hear something you like? Then, as always, "shop around".
And with that in mind, why not listen to one of the finest Lohengrin ever recorded that alas, not enough people have either heard or own.