You'll be able to use the SM58 at live gigs later but, starting out, it will get you a presence on Youtube or for simple projects. Right now, my neighbors' TV is blaring, their dogs are barking, and the mic doesn't pick it up. It doesn't pick up anything noticable past around 6-12 inches — loud noises at 24 inches — and the very small amount of noise it does pick up is removed without severely damaging the sound quality.

Now, is that a proper studio setup? No. But I'll use the mic when I get one. SM58s can be dropped from buildings and still work and pros continue to use them at live appearances. (You'll also want an SM57 for instruments.) Some pros use them in studios.

But the expenses of a quality booth become an excuse not to make stuff, whether it's speeches, music, or voiceover. And if you aren't producing anything, you won't be able to justify the bigger expenses later. That is what leads people to wake up one day at 30, 35, or 40 and give up. The people who advise you to go in big initially had the money to do it and are part of a select group that made it.

Think about it: you only ask the successful people for advice. I would imagine that the majority of people who bought a WhisperRoom blew the money or eventually spent enough on upgrades to be run a negative. But you only hear from the successful people because that's who people seek advice from.

I'd say get a solid dynamic mic like the SM58 and start making stuff now. Rent a booth for an album or run a Kickstarter that folds the booth into your budget. It's easier to get other people to help diffray the risk of a large purchase if you have functional samples.