Here's my suggested shopping list for singing gear and why for each piece.
Shure SM58 ($100) - Most commonly used as a touring microphone for live performance, it is a beast that you won't have to be as careful with like most condensers. If you drop it, it will still work. It's also the industry standard live mic and works very well in a studio setting. Let me assure you that you do NOT want a USB mic if you're doing any kind of work that doesn't involve sitting at a desk. Extending short USB cables is a pain in the a**, and the cost of a 20 foot or longer XLR cable is negligible (especially if you are buying a bunch of gear from one shop, usually you can negotiate for them to throw in the cables). There is some slight difference in sound but most people can't tell the difference. Now, the SM58 is a dynamic mic, not a condenser but the tech inside the microphone does not in all cases determine it's purpose. Even if you pick up more specialized mics later on, you will never get rid of your SM58, I promise you that.
Shure SM57 ($150) - An exceptional intrument microphone that also does pretty well for spoken word (Those 2 mics on the presidents podium during his speeches are SM57's with wind screens).
Behringer/Alesis/Mackie mixing board (from $50 to $200 depending on how many channels you think you will need in the future. I'd suggest going 8 just in case. Nothing sucks worse than running a few mics and one of your channels dies on you.) - These are mid/lower cost mixing boards. Buy one with a USB interface and it will now double as your sound card. Remember that the channels of a mixing board are not all XLR, so at a bare minimum make sure it has 2 XLR channels. Some mixing boards include effects as well which is slick.
Presonus TubePre (Preamp - $100) - Now, the preamps in most low grade mixing boards are usually a bit rough. Yes they will pump your sound up but expect noise added to the mix. The TubePre is a decent quiet preamp that should get you the pump that you need. However, I would suggest waiting until after you have gotten the mixer and mix. Test them together first and see if you even need it. You might not.
A note on cables. Try to get the place you're buying from (if not online) to throw in the cables for free. But, if all they offer is the cheapest cable they have, ask if you can go one up and pay the difference. I'm refering to quality of cable and not length here. The lowest quality cables have a tendancy to have poor connnectors and insulation resulting in noise or cable failure more often than higher quality cables. No particular brand is "the one" but stay away from Monster because they're always overpriced by a good 100%.
I would also recommend that you avoid the Blue Yeti for anything but podcasting or basic spoken word.